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Sample records for increased molecular weight

  1. Irradiated aromatic polysulphones of increased flow resistance and molecular weight

    Staniland, P.A.; Jarrett, W.G.

    1976-01-01

    Aromatic polymers of increased resistance to flow and molecular weight are obtained by irradiation using β-rays or γ-rays at temperatures up to 400 0 C of an aromatic polymer whose molecular chains comprise benzenoid groups and bivalent linking groups, and where irradiation is γ-rays by heating subsequent to irradiation at 200 to 400 0 C

  2. Aromatic polymers of increased resistance to flow and molecular weight obtained by irradiation

    Staniland, P.A.; Jarrett, G.

    1976-01-01

    Aromatic polymers of increased resistance to flow and increased molecular weight are obtained by irradiation using β rays or gamma rays at temperatures up to 400 0 C of an aromatic polymer whose molecular chains comprise benzenoid groups and bivalent linking groups, and where irradiation is gamma rays by heating subsequent to irradiation at 200 0 C to 400 0 C. The polymeric materials having increased molecular weight are useful for coating non-cooking surfaces of cookware

  3. Low-molecular weight heparin increases circulating sFlt-1 levels and enhances urinary elimination.

    Henning Hagmann

    Full Text Available RATIONALE: Preeclampsia is a devastating medical complication of pregnancy which leads to maternal and fetal morbidity and mortality. While the etiology of preeclampsia is unclear, human and animal studies suggest that excessive circulating levels of soluble fms-like tyrosine-kinase-1 (sFlt-1, an alternatively spliced variant of VEGF-receptor1, contribute to the signs and symptoms of preeclampsia. Since sFlt-1 binds to heparin and heparan sulfate proteoglycans, we hypothesized that the anticoagulant heparin, which is often used in pregnancy, may interfere with the levels, distribution and elimination of sFlt-1 in vivo. OBJECTIVE: We systematically determined serum and urine levels of angiogenic factors in preeclamptic women before and after administration of low molecular weight heparin and further characterized the interaction with heparin in biochemical studies. METHODS AND RESULTS: Serum and urine samples were used to measure sFlt-1 levels before and after heparin administration. Serum levels of sFlt-1 increased by 25% after heparin administration in pregnant women. The magnitude of the increase in circulating sFlt-1 correlated with initial sFlt-1 serum levels. Urinary sFlt-1 levels were also elevated following heparin administration and levels of elimination were dependent on the underlying integrity of the glomerular filtration barrier. Biochemical binding studies employing cation exchange chromatography revealed that heparin bound sFlt-1 had decreased affinity to negatively charged surfaces when compared to sFlt-1 alone. CONCLUSION: Low molecular weight heparin administration increased circulating sFlt1 levels and enhanced renal elimination. We provide evidence that both effects may be due to heparin binding to sFlt1 and masking the positive charges on sFlt1 protein.

  4. A 7-d exercise program increases high-molecular weight adiponectin in obese adults

    Kelly, Karen R; Blaszczak, Alecia; Haus, Jacob M

    2012-01-01

    High-molecular weight (HMW) adiponectin is the biologically active form of adiponectin and is related to enhanced insulin sensitivity and metabolic function. Previously, we found that 7 d of exercise improves insulin sensitivity in obese subjects; however, whether short-term exercise training...

  5. Dim light at night disrupts molecular circadian rhythms and increases body weight.

    Fonken, Laura K; Aubrecht, Taryn G; Meléndez-Fernández, O Hecmarie; Weil, Zachary M; Nelson, Randy J

    2013-08-01

    With the exception of high latitudes, life has evolved under bright days and dark nights. Most organisms have developed endogenously driven circadian rhythms that are synchronized to this daily light/dark cycle. In recent years, humans have shifted away from the naturally occurring solar light cycle in favor of artificial and sometimes irregular light schedules produced by electric lighting. Exposure to unnatural light cycles is increasingly associated with obesity and metabolic syndrome; however, the means by which environmental lighting alters metabolism are poorly understood. Thus, we exposed mice to dim light at night and investigated changes in the circadian system and metabolism. Here we report that exposure to ecologically relevant levels of dim (5 lux) light at night altered core circadian clock rhythms in the hypothalamus at both the gene and protein level. Circadian rhythms in clock expression persisted during light at night; however, the amplitude of Per1 and Per2 rhythms was attenuated in the hypothalamus. Circadian oscillations were also altered in peripheral tissues critical for metabolic regulation. Exposure to dimly illuminated, as compared to dark, nights decreased the rhythmic expression in all but one of the core circadian clock genes assessed in the liver. Additionally, mice exposed to dim light at night attenuated Rev-Erb expression in the liver and adipose tissue. Changes in the circadian clock were associated with temporal alterations in feeding behavior and increased weight gain. These results are significant because they provide evidence that mild changes in environmental lighting can alter circadian and metabolic function. Detailed analysis of temporal changes induced by nighttime light exposure may provide insight into the onset and progression of obesity and metabolic syndrome, as well as other disorders involving sleep and circadian rhythm disruption.

  6. Low-Molecular-Weight Chitosan Supplementation Increases the Population of Prevotella in the Cecal Contents of Weanling Pigs

    Ting Yu

    2017-11-01

    Full Text Available Low-molecular-weight chitosan (LC promoted growth in weaned piglets as an alternative to feed-grade antibiotics. To investigate the influence of LC supplementation on piglets' gut microbiome and compare the differences in community composition between LC and antibiotics with ZnO addition, we assessed the cecal microbial community by 16S rRNA gene sequencing with three treatments consisting of basal diet (CTR group, basal diet with low-molecular-weight chitosan (LC group, and basal diet with antibiotic and ZnO (AZ group. LC decreased pH more than AZ did in the cecum (both compared to CTR. Beta diversity analysis showed that community structure was distinctly different among the CTR, LC, and AZ treatments, indicating that either LC or AZ treatment modulated the piglet microbiota. Bacteroidetes, Firmicutes, and Proteobacteria dominated the community [>98% of operational taxonomic units (OTUs] in piglet cecal contents. Compared to CTR, both LC, and AZ increased the relative abundance of Bacteroidetes while they decreased the count of Firmicutes and AZ decreased the population of Proteobacteria. In CTR the top four abundant genera were Prevotella (~10.4%, Succinivibrio (~6.2%, Lactobacillus (~5.6%, and Anaerovibrio (5.4%. Both LC and AZ increased the relative abundance of Prevotella but decreased the ratio of Lactobacillus when they compared with CTR. Moreover, LC increased the relative abundance of Succinivibrio and Anaerovibrio while AZ decreased them. The microbial function prediction showed LC enriched more pathways in the metabolism of cofactors and vitamins than CTR or AZ did. LC may potentially function as an alternative to feed-grade antibiotics in weaned piglets due to its beneficial regulation of the intestinal microbiome.

  7. Higher molecular weight polyethylene glycol increases cell proliferation while improving barrier function in an in vitro colon cancer model.

    Bharadwaj, Shruthi; Vishnubhotla, Ramana; Shan, Sun; Chauhan, Chinmay; Cho, Michael; Glover, Sarah C

    2011-01-01

    Polyethylene glycol (PEG) has been previously shown to protect against enteric pathogens and prevent colon cancer invasion. To determine if PEG could indeed protect against previously observed pro-invasive effects of commensal E. coli and EPEC, Caco-2 cells grown in an in vitro model of colon cancer were infected with strains of human commensal E. coli or EPEC and treated with 10% PEG 3350, PEG 8000, and PEG 20,000, respectively. At 24 hours after infection, MMP-1 and MMP-13 activities, cell cluster thickness, depth of invasion, and proliferation were determined using standard molecular biology techniques and advanced imaging. We found that higher molecular weight PEG, especially PEG 8000 and 20,000, regardless of bacterial infection, increased proliferation and depth of invasion although a decrease in cellular density and MMP-1 activity was also noted. Maximum proliferation and depth of invasion of Caco-2 cells was observed in scaffolds treated with a combination of commensal E. coli strain, HS4 and PEG 8000. In conclusion, we found that PEG 8000 increased cell proliferation and led to the preservation of cell density in cells treated with commensal bacteria. This is important, because the preservation of a proliferative response in colon cancer results in a more chemo-responsive tumor.

  8. Higher Molecular Weight Polyethylene Glycol Increases Cell Proliferation While Improving Barrier Function in an In Vitro Colon Cancer Model

    Shruthi Bharadwaj

    2011-01-01

    Full Text Available Polyethylene glycol (PEG has been previously shown to protect against enteric pathogens and prevent colon cancer invasion. To determine if PEG could indeed protect against previously observed pro-invasive effects of commensal E. coli and EPEC, Caco-2 cells grown in an in vitro model of colon cancer were infected with strains of human commensal E. coli or EPEC and treated with 10% PEG 3350, PEG 8000, and PEG 20,000, respectively. At 24 hours after infection, MMP-1 and MMP-13 activities, cell cluster thickness, depth of invasion, and proliferation were determined using standard molecular biology techniques and advanced imaging. We found that higher molecular weight PEG, especially PEG 8000 and 20,000, regardless of bacterial infection, increased proliferation and depth of invasion although a decrease in cellular density and MMP-1 activity was also noted. Maximum proliferation and depth of invasion of Caco-2 cells was observed in scaffolds treated with a combination of commensal E. coli strain, HS4 and PEG 8000. In conclusion, we found that PEG 8000 increased cell proliferation and led to the preservation of cell density in cells treated with commensal bacteria. This is important, because the preservation of a proliferative response in colon cancer results in a more chemo-responsive tumor.

  9. Improved synthesis with high yield and increased molecular weight of poly(alpha,beta-malic acid) by direct polycondensation.

    Kajiyama, Tetsuto; Kobayashi, Hisatoshi; Taguchi, Tetsushi; Kataoka, Kazunori; Tanaka, Junzo

    2004-01-01

    The development of synthetic biodegradable polymers, such as poly(alpha-hydroxy acid), is particularly important for constructing medical devices, including scaffolds and sutures, and has attracted growing interest in the biomedical field. Here, we report a novel approach to preparing high molecular weight poly(malic acid) (HMW--PMA) as a biodegradable and bioabsorbable water-soluble polymer. We investigated in detail the reaction conditions for the simple direct polycondensation of l-malic acid, including the reaction times, temperatures, and catalysts. The molecular weight of synthesized alpha,beta-PMA is dependent on both the reaction temperature and time. The optimum reaction condition to obtain alpha,beta-PMA by direct polycondensation using tin(II) chloride as a catalyst was thus determined to be 110 degrees C for 45 h with a molecular weight of 5300. The method for alpha,beta-PMA synthesis established here will facilitate production of alpha,beta-PMA of various molecular weights, which may have a potential utility as biomaterials.

  10. Solid-State Polymerization of Poly(ethylene furanoate Biobased Polyester, I: Effect of Catalyst Type on Molecular Weight Increase

    Nejib Kasmi

    2017-11-01

    Full Text Available In this work, we report the synthesis of poly(ethylene furanoate (PEF, catalyzed by three different catalysts, namely, titanium (IV isopropoxide (TIS, tetrabutyltitanate (TBT, and dibutyltin (IV oxide (DBTO, via the two-stage melt polycondensation method. Solid-state polymerization (SSP was conducted at different reaction times (1, 2, 3.5, and 5 h and temperatures 190, 200, and 205 °C, under vacuum. The resultant polymers were analyzed according to their intrinsic viscosity (IV, end groups (–COOH, and thermal properties, via differential scanning calorimetry. DSC results showed that the post polymerization process was favorable to enhance the melting point of the prepared PEF samples. As was expected, the intrinsic viscosity and the average molecular weight of PEF increased with the SSP time and temperature, whereas the number of carboxyl end-groups was decreased. A simple kinetic model was also developed and used to predict the time evolution of polymers IV, as well as the carboxyl and hydroxyl content of PEF during the SSP. From both the experimental measurements and the theoretical simulation results it was proved that the presence of the TIS catalyst resulted in higher transesterification kinetic rate constants and higher reaction rates. The activation energies were not much affected by the presence of different catalysts. Finally, using DBTO as a catalyst, the polyesters produced have higher crystallinity, and as a consequence, higher number of inactive carboxyl and hydroxyl groups.

  11. High molecular weight hyaluronic acid increases the differentiation potential of the murine chondrocytic ATDC5 cell line.

    Sato, Eiichi; Ando, Takashi; Ichikawa, Jiro; Okita, Genki; Sato, Nobutaka; Wako, Masanori; Ohba, Tetsuro; Ochiai, Satoshi; Hagino, Tetsuo; Jacobson, Richard; Haro, Hirotaka

    2014-12-01

    Osteoarthritis (OA) is a group of common, chronic, and painful inflammatory joint diseases. One important finding in OA patients is a remarkable decrease in the molecular weight of hyaluronic acid (HA) in the synovial fluid of affected joints. Therapeutic HA is available to patients in most parts of the world as a viscosupplementation product for the treatment of OA. Previous clinical reports show that high molecular weight HA (HMWHA) more effectively relieves pain than low molecular weight HA (LMWHA). However, the mechanism behind this finding remains unclear. In this study, we investigated whether a LMWHA (Low-0.9 MDa) and two types of HMWHA (High-1.9 MDa and 6 MDa) differentially affected chondroregulatory action. We tested this using ATDC5 cell, a murine chondrocytic cell line widely used in culture systems to study chondrogenic differentiation. We found that HMWHA, especially hylan G-F 20 (High-6 MDa), significantly induced aggrecan and proteoglycan accumulation, nodule formation, and mRNA expression of chondrogenic differentiation markers in a time- and dose-dependent manner. In addition, we showed that HMWHA prevented TNF-α induced inhibition of chondrogenic differentiation, with no effect on cell proliferation or viability. These results reveal that HMWHA significantly promotes chondrogenic differentiation of ATDC5 cells in vitro, and suggest that HMWHA plays a significant chondroregulatory role in vivo. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  12. Increase in 4-coumaryl alcohol units during lignification in alfalfa (Medicago sativa) alters the extractability and molecular weight of lignin.

    Ziebell, Angela; Gracom, Kristen; Katahira, Rui; Chen, Fang; Pu, Yunqiao; Ragauskas, Art; Dixon, Richard A; Davis, Mark

    2010-12-10

    The lignin content of biomass can impact the ease and cost of biomass processing. Lignin reduction through breeding and genetic modification therefore has potential to reduce costs in biomass-processing industries (e.g. pulp and paper, forage, and lignocellulosic ethanol). We investigated compositional changes in two low-lignin alfalfa (Medicago sativa) lines with antisense down-regulation of p-coumarate 3-hydroxylase (C3H) or hydroxycinnamoyl-CoA:shikimate hydroxycinnamoyltransferase (HCT). We investigated whether the difference in reactivity during lignification of 4-coumaryl alcohol (H) monomers versus the naturally dominant sinapyl alcohol and coniferyl alcohol lignin monomers alters the lignin structure. Sequential base extraction readily reduced the H monomer content of the transgenic lines, leaving a residual lignin greatly enriched in H subunits; the extraction profile highlighted the difference between the control and transgenic lines. Gel permeation chromatography of isolated ball-milled lignin indicated significant changes in the weight average molecular weight distribution of the control versus transgenic lines (CTR1a, 6000; C3H4a, 5500; C3H9a, 4000; and HCT30a, 4000).

  13. Children with atopic dermatitis and frequent emollient use have increased urinary levels of low-molecular-weight phthalate metabolites and parabens

    Overgaard, L E K; Main, K M; Frederiksen, H

    2017-01-01

    BACKGROUND: Parabens may be added to cosmetic and personal care products for preservation purposes. Low-molecular weight (LMW) phthalate diesters function as plasticizers, fixatives or solvents in such products, but may also be found in small quantities as contaminants from plastic containers...... whether the difference is explained by increased use of the specific emollients that are used to treat pruritic and inflamed skin, and/or whether the impaired skin barrier allows chemicals to penetrate more easily. Moreover, the putative toxicological burden is unknown....

  14. Investigation of Galactosylated Low Molecular Weight Chitosan ...

    was coupled with low molecular weight chitosan (LMWC) using carbodiimide chemistry. .... High molecular weight chitosan (minimum 85% ..... membrane permeability of drug and mutual repulsion ... coating thickness and the lower solubility of.

  15. Improved Yield of High Molecular Weight DNA Coincides with Increased Microbial Diversity Access from Iron Oxide Cemented Sub-Surface Clay Environments

    Hurt, Richard A.; Robeson, Michael S.; Shakya, Migun; Moberly, James G.; Vishnivetskaya, Tatiana A.; Gu, Baohua; Elias, Dwayne A.

    2014-01-01

    Despite over three decades of progress, extraction of high molecular weight (HMW) DNA from high clay soils or iron oxide cemented clay has remained challenging. HMW DNA is desirable for next generation sequencing as it yields the most comprehensive coverage. Several DNA extraction procedures were compared from samples that exhibit strong nucleic acid adsorption. pH manipulation or use of alternative ion solutions offered no improvement in nucleic acid recovery. Lysis by liquid N2 grinding in concentrated guanidine followed by concentrated sodium phosphate extraction supported HMW DNA recovery from clays high in iron oxides. DNA recovered using 1 M sodium phosphate buffer (PB) as a competitive desorptive wash was 15.22±2.33 µg DNA/g clay, with most DNA consisting of >20 Kb fragments, compared to 2.46±0.25 µg DNA/g clay with the Powerlyzer system (MoBio). Increasing PB concentration in the lysis reagent coincided with increasing DNA fragment length during initial extraction. Rarefaction plots of 16S rRNA (V1–V3 region) pyrosequencing from A-horizon and clay soils showed an ∼80% and ∼400% larger accessed diversity compared to the Powerlyzer soil DNA system, respectively. The observed diversity from the Firmicutes showed the strongest increase with >3-fold more operational taxonomic units (OTU) recovered. PMID:25033199

  16. Increased synthesis of high-molecular-weight cPLA2 mediates early UV-induced PGE2 in human skin.

    Gresham, A; Masferrer, J; Chen, X; Leal-Khouri, S; Pentland, A P

    1996-04-01

    Ultraviolet light (UV) B-induced inflammation is characterized by dramatic increases in prostaglandin E2 (PGE2) synthesis due to enhanced arachidonate deacylation from the membrane. Therefore, the effect of UV on sythesis, mass, and distribution of the high-molecular-weight phospholipase A2 (cPLA2) in cultured human keratinocytes and human skin was studied. The 105-kDa cPLA2 was demonstrated to be the critical enzyme in UV-induced PGE2 synthesis and erythema in the first 6 h postirradiation. Immunoprecipitation of 35S-labeled protein showed cPLA2 synthesis increased three- to fourfold 6 h after irradiation. Immunoprecipitated 32P-labeled cPLA2 demonstrated phosphorylation of cPLA2 was concurrently induced, suggesting that UV also activates cPLA2. This increase in cPLA2 synthesis and activation also closely correlated with increased PGE2 synthesis and [3H]arachidonic acid release and was effectively blocked by both an S-oligonucleotide antisense to cPLA2 and methyl arachidonate fluorophosphate, a specific inhibitor of cPLA2. Biopsy and histochemical examination of erythematous sites expressed increased amounts of cPLA2 whereas nonerythematous irradiated sites did not. In contrast, cyclooxygenase-1 and -2 in cultures and skin explants were unaffected 6 h post-UV, and no change in cyclooxygenase activity was observed at this time. These results suggest that increased cPLA2 synthesis occurs only when skin is exposed to UV doses that are sufficient to cause erythema and indicate expression of cPLA2 participates in acute UV inflammation.

  17. The effect of monomer molecular weight on grafting reaction

    Wu Minghong; Ding Zhongli; Ma Zueteh

    1995-01-01

    In this paper, some condensed ethylene glycol acrylate monomers with different molecular weight being grafted to the PE film by means of pre-irradiation is reported. The effect of molecular weight of monomer on grafting reaction and the hydrophilicity of grafting sample have been discussed. The experimental results show: molar degrees of grafting decreased non-linearly with the increasement of molecular weight of monomer, the grafting reaction of polymer is greater effected by the swelling degree of PE film, the greater the swelling degree of grafting material, the higher the grating degree grafting is, the initial rate of grafting reaction decreased with the increasement of molecular weight of monomer. (author)

  18. Molecular weight distribution of Athabasca bitumen

    Champagne, P J; Manolakis, E; Ternan, M

    1985-03-01

    A sample of whole Athabasca bitumen has been fractionated by preparative g.p.c. The weights of the fractions have been determined and their molecular weights measured by several methods. In contras to previously published data, consistent results were obtained using different solvents (THF, benzene/water) and using different techniques (v.p.o., f.p.d. and g.c.-m.s.). This has resulted in a accurate definition of the molecular weight distribution of Athabasca bitumen.

  19. Molecular weight characterisation of synthetic polymers

    Holding, Steve R

    1995-01-01

    The report comprises a state-of-the-art overview of the subject of molecular weight characterisation, supported by an extensive, indexed bibliography. The bibliography contains over 400 references and abstracts, compiled from the Polymer Library.

  20. High Molecular Weight Melanoidins from Coffee Brew

    Bekedam, E.K.; Schols, H.A.; Boekel, van T.; Smit, G.

    2006-01-01

    The composition of high molecular weight (HMw) coffee melanoidin populations, obtained after ethanol precipitation, was studied. The specific extinction coefficient (Kmix) at 280, 325, 405 nm, sugar composition, phenolic group content, nitrogen content, amino acid composition, and non-protein

  1. Nasal Delivery of High Molecular Weight Drugs

    Erdal Cevher

    2009-09-01

    Full Text Available Nasal drug delivery may be used for either local or systemic effects. Low molecular weight drugs with are rapidly absorbed through nasal mucosa. The main reasons for this are the high permeability, fairly wide absorption area, porous and thin endothelial basement membrane of the nasal epithelium. Despite the many advantages of the nasal route, limitations such as the high molecular weight (HMW of drugs may impede drug absorption through the nasal mucosa. Recent studies have focused particularly on the nasal application of HMW therapeutic agents such as peptide-protein drugs and vaccines intended for systemic effects. Due to their hydrophilic structure, the nasal bioavailability of peptide and protein drugs is normally less than 1%. Besides their weak mucosal membrane permeability and enzymatic degradation in nasal mucosa, these drugs are rapidly cleared from the nasal cavity after administration because of mucociliary clearance. There are many approaches for increasing the residence time of drug formulations in the nasal cavity resulting in enhanced drug absorption. In this review article, nasal route and transport mechanisms across the nasal mucosa will be briefly presented. In the second part, current studies regarding the nasal application of macromolecular drugs and vaccines with nanoand micro-particulate carrier systems will be summarised.

  2. Molecular weights and molecular weight distributions of irradiated cellulose fibers by gel permeation chromatography

    Kusama, Y.; Kageyama, E.; Shimada, M.; Nakamura, Y.

    1976-01-01

    Radiation degradation of cellulose fibers was investigated by gel permeation chromatography (GPC). Scoured cotton of Mexican variety (cellulose I), Polynosic rayon (cellulose II), and their microcrystalline celluloses obtained by hydrolysis of the original fibers were irradiated by Co-60 γ-rays under vacuum or humid conditions. The irradiated samples were then nitrated under nondegradative conditions. The molecular weights and molecular weight distributions were measured by GPC using tetrahydrofuran as solvent. The relationship between molecular weight and elution count was obtained with cellulose trinitrate standards fractionated by preparative GPC. The degree of polymerization of the fibers decreased with increasing irradiation dose, but their microcrystalline celluloses were only slightly degraded by irradiation, especially in microcrystalline cellulose from cellulose I. Degradation of the fibers irradiated under humid conditions was less than that irradiated under vacuum. It was found that the G-values for main-chain scission for the irradiated cellulose I, cellulose II, microcrystalline cellulose I, and microcrystalline cellulose II were 2.8, 2.9, less than 1, and 2.9, respectively, but the G-value for main-chain scission for the irradiated cellulose II was increased to 11.2 at irradiation doses above 3 Mrad. Consequently, it is inferred that cellulose molecules in the amorphous regions are degraded more readily, and the well-aligned molecules in crystalline regions are not as easily degraded by irradiation

  3. Sintering of ultra high molecular weight polyethylene

    Abstract. Ultra high molecular weight polyethylene (UHMWPE) is a high performance polymer having low coefficient of friction, good abrasion resistance, good chemical ... In this study, we report our results on compaction and sintering behaviour of two grades of UHMWPE with reference to the powder morphology, sintering ...

  4. Alkyl cross-linked low molecular weight polypropyleneimine dendrimers as efficient gene delivery vectors

    Faezeh Moghadam Ariaee

    2016-10-01

    Conclusion: Our results indicated that oligomerization of low molecular weight PPI (PPI G2-alkyl-PPI G2 conjugate could be an approach to increase the transfection efficiency and to lower the cytotoxicity of low molecular weight polycations.

  5. Effect of increasing truck weight on bridges.

    2010-09-01

    Legislation has been proposed that will allow a 17,000 lb increase in the maximum gross vehicle : weight on the Interstate Highway System. This projects main goal is quantify the effect of this : increase on the internal forces to which typical sl...

  6. Low molecular weight block copolymers as plasticizers for polystyrene

    Hansen, Kristoffer Karsten; Nielsen, Charlotte Juel; Hvilsted, Søren

    2005-01-01

    /mol and minimum polystyrene content of 50 w/w%, which by us is predicted as the limits for solubility of polystyrene-b-alkyl in polystyrene. DSC showed polystyrene was plasticized, as seen by a reduction in glass transition temperature, by block copolymers consisting of a polystyrene block with molecular weight...... of approximately 1 kg/mol and an alkyl block with a molecular weight of approximately of 0.3 kg/mol. The efficiency of the block copolymers as plasticizers increases with decreasing molecular weight and polystyrene content. In addition, polystyrene-b-alkyl is found to be an efficient plasticizer also...... for polystyrene-b-polyisoprene-b-polystyrene (SIS) block copolymers. The end use properties of SIS plasticized with polystyrene-b-alkyl, measured as tensile strength, is higher than for SIS plasticized with dioctyl adipate. The polystyrene-b-polybutadiene-b-polystyrene and polystyrene-bpoly(propylene glycol...

  7. Polymer Molecular Weight Analysis by [Superscript 1]H NMR Spectroscopy

    Izunobi, Josephat U.; Higginbotham, Clement L.

    2011-01-01

    The measurement and analysis of molecular weight and molecular weight distribution remain matters of fundamental importance for the characterization and physical properties of polymers. Gel permeation chromatography (GPC) is the most routinely used method for the molecular weight determination of polymers whereas matrix-assisted laser…

  8. Weight Rhythms: Weight Increases during Weekends and Decreases during Weekdays

    Anna-Leena Orsama

    2014-01-01

    Full Text Available Background/Aims: The week's cycle influences sleep, exercise, and eating habits. An accurate description of weekly weight rhythms has not been reported yet - especially across people who lose weight versus those who maintain or gain weight. Methods: The daily weight in 80 adults (BMI 20.0-33.5 kg/m2; age, 25-62 years was recorded and analysed to determine if a group-level weekly weight fluctuation exists. This was a retrospective study of 4,657 measurements during 15-330 monitoring days. Semi-parametric regression was used to model the rhythm. Results: A pattern of daily weight changes was found (p Conclusion: Weight variations between weekends and weekdays should be considered as normal instead of signs of weight gain. Those who compensate the most are most likely to either lose or maintain weight over time. Long-term habits may make more of a difference than short-term splurges. People prone to weight gain could be counselled about the importance of weekday compensation.

  9. Modeling of molecular weight and molecular weight distribution in slurry polymerization of propylene by Ziegler-Natta catalysts

    Khorasani, R.; Pourmahdian, S.

    2007-01-01

    The Precise prediction of polypropylene synthesized by heterogeneous Ziegler-Natta catalysts needs good knowledge of parameters affecting on polymerization. molecular weight and molecular weight distribution are among important characteristics of a polymer determining physical-mechanical properties. broadening of molecular weight distribution is an important and well known characteristic of polypropylene synthesized by heterogeneous Ziegler-Natta catalysts, So it is important to understand the origin of broad molecular weight. Two main factors in broadening molecular weight, namely mass transfer resistances and multiplicity of active sites, are discussed in this paper and a model including these factors is presented. Then we calculate molecular weight and molecular weight distribution by the model and compare our results with

  10. Molecular Formula and Molecular Weight - NBDC NikkajiRDF | LSDB Archive [Life Science Database Archive metadata

    Full Text Available List Contact us NBDC NikkajiRDF Molecular Formula and Molecular Weight Data detail Data name Molecular Formula and Molecul...- Description of data contents This RDF data includes molecular formula and molecular weight of chemical sub...ikkajiRDF_MFMW.tar.gz File size: 404 MB Simple search URL - Data acquisition method The data was converted from data of molecul...ar formulas and molecular weights in Basic Information ( http://dbarchive.biosciencedbc.j... Policy | Contact Us Molecular Formula and Molecular Weight - NBDC NikkajiRDF | LSDB Archive ...

  11. Radiation degradation of molasses pigment. 2. Molecular weight fraction

    Sawai, Teruko; Sekiguchi, Masayuki; Tanabe, Hiroko

    1996-01-01

    Water demand in Tokyo has increased rapidly. Because of the scarcity of water sources within the city, Tokyo is dependent on water from other prefectures. Recycling of municipal effluent is an effective means of coping with water shortage in Tokyo. We have studied the radiation treatment of waste water for recycling. The degradation of molasses pigments in waste water from yeast factory by radiation was investigated. The dialyzed molasses pigments and non-dialyzed samples in waste waters were compared in chromaticity, UV absorption, color different and COD. The dialysis and fractionation by permeable membrane were carried out with Seamless Cellulose tubing (Union Carbide Corporation) and spectra/Por membrane (Spectrum Medical Industries INC.) The TOC values decreased and the dark brown color faded with increasing dose. The high molecular weight components of molasses pigment were degraded to lower molecular weight substances and decomposed to carbon dioxide. The relationships between the value of chromaticity/TOC and molecular weight of molasses pigments were obtained by radiation. (author)

  12. Synthesis and properties of ionic polyurethane dispersions: influence of polyol molecular weight

    Valipour Ebrahimi, M.; Barikani, M.; Mohammad Seyed Mohaghegh, S.

    2006-01-01

    A series of water dispersible polyurethanes containing carboxylate anion as the hydrophilic pendant group were prepared from toluene diisocyanate (TDI), 1,4- butanediol (1,4-BDO), dimethylol propionic acid and different molecular weight of polytetramethylene glycol . IR Spectroscopy was used to check the end of polymerization reaction and characterization of polymer. The effect of polytetramethylene glycol molecular weight was studied on the particle size distribution, contact angle, and mechanical and thermal properties of the emulsion-cast films. Average particle size of prepared polyurethane emulsions decreases with increasing the polytetramethylene glycol molecular weight. Tensile strength and hardness decrease and elongation-at-break and contact angle increase with increase of the polytetramethylene glycol molecular weight. Thermal property and thermal stability are also effected by variation of polytetramethylene glycol molecular weight. The thermal stability increases with increasing polytetramethylene glycol molecular weight. Glass transition temperature (T g ) moved toward the lower temperatures by increasing molecular weight of the polyol. Decrease in T g and tensile properties are interpreted in terms of the decrease in hard segments and the increase in chain flexibility and phase separation in high molecular weight polytetramethylene glycol based polyurethane

  13. Effect of Sulfation and Molecular Weight on Anticoagulant Activity of Dextran.

    Drozd, N N; Logvinova, Yu S; Torlopov, M A; Udoratina, E V

    2017-02-01

    Sulfation (to 2.8) of dextrans with molecular weight of 150 and 20 kDa was followed by the appearance of anticoagulant activity that increased with decreasing their molecular weight and did not depend on antithrombin, plasma inhibitor of serine proteases of the blood coagulation system. Antithrombin activity of dextran sulfate with a molecular weight of 20 kDa reached 12.6-15.3 U/mg. Dextran sulfates with molecular weights of 20 and 150 kDa did not potentiate ADP-induced human platelet aggregation.

  14. Hydrodynamic characterization and molecular weight estimation of ultrasonically sheared DNA

    Casal, J. I.; Garces, F.; Garcia-Sacristan, A.

    1981-01-01

    The sedimentation coefficients and intrinsic viscosities of ultrasonically sheared calf thymus DNA have been determined. The molecular weight estimation according to this parameters have been compared with the ones obtained from the electrophoretic migration rates based on the calibration proposed using the known molecular weight restriction fragments of X-ENA. (Author) 35 refs

  15. Anticoagulant effect of low molecular weight heparin on central ...

    Purpose: To analyse the effect of low molecular weight heparin on venous catheters in haemodialysis patients. Methods: This study included 140 eligible patients who were randomly and evenly divided into two groups, viz, a study group that received low molecular weight heparin and a control group that received ...

  16. Hydrodynamic caracterization and molecular weight stimation of ultrasonically sheared DNA

    Garces, F.; Casal, J.I.; Garcia, A.

    1981-01-01

    The sedimentation coefficients and intrinsec viscosities of ultrasonically sheared calf thymus DNA have been determined. The molecular weight stimation according to this parameters have been compared with the ones obtained from the electrophoretic migration rates based on the calibration proposed using the known molecular weight restriction fragments of lambds-DNA. (author) [es

  17. Controlling silk fibroin microspheres via molecular weight distribution

    Zeng, Dong-Mei; Pan, Jue-Jing; Wang, Qun; Liu, Xin-Fang; Wang, Hui; Zhang, Ke-Qin

    2015-01-01

    Silk fibroin (SF) microspheres were produced by salting out SF solution via the addition of potassium phosphate buffer solution (K 2 HPO 4 –KH 2 PO 4 ). The morphology, size and polydispersity of SF microspheres were adjusted by changing the molecular weight (MW) distribution and concentration of SF, as well as the ionic strength and pH of the buffer solution. Changing the conditions under which the SF fiber dissolved in the Lithium Boride (LiBr) solution resulted in altering the MW distribution of SF solution. Under optimal salting-out conditions (ionic strength > 0.7 M and pH > 7) and using a smaller and narrower SF MW distribution, SF microspheres with smoother shapes and more uniform sizes were produced. Meanwhile, the size and polydispersity of the microspheres increased when the SF concentration was increased from 0.25 mg/mL to 20 mg/mL. The improved SF microspheres, obtained by altering the distribution of molecular weight, have potential in drug and gene delivery applications. - Highlights: • MW distribution was changed by applying different dissolving methods of SF fiber. • Smaller and narrower MW distribution improves the quality of SF microspheres. • Size and polydispersity of microspheres increase as SF concentration increases. • Improved SF microspheres have potential in drug and gene delivery applications

  18. Controlling silk fibroin microspheres via molecular weight distribution

    Zeng, Dong-Mei; Pan, Jue-Jing; Wang, Qun; Liu, Xin-Fang; Wang, Hui [National Engineering Laboratory for Modern Silk, College for Textile and Clothing Engineering, Soochow University, Suzhou, Jiangsu 215123 (China); Zhang, Ke-Qin, E-mail: kqzhang@suda.edu.cn [National Engineering Laboratory for Modern Silk, College for Textile and Clothing Engineering, Soochow University, Suzhou, Jiangsu 215123 (China); Research Center of Cooperative Innovation for Functional Organic/Polymer Material Micro/Nanofabrication, Soochow University, Suzhou, Jiangsu 215123 (China)

    2015-05-01

    Silk fibroin (SF) microspheres were produced by salting out SF solution via the addition of potassium phosphate buffer solution (K{sub 2}HPO{sub 4}–KH{sub 2}PO{sub 4}). The morphology, size and polydispersity of SF microspheres were adjusted by changing the molecular weight (MW) distribution and concentration of SF, as well as the ionic strength and pH of the buffer solution. Changing the conditions under which the SF fiber dissolved in the Lithium Boride (LiBr) solution resulted in altering the MW distribution of SF solution. Under optimal salting-out conditions (ionic strength > 0.7 M and pH > 7) and using a smaller and narrower SF MW distribution, SF microspheres with smoother shapes and more uniform sizes were produced. Meanwhile, the size and polydispersity of the microspheres increased when the SF concentration was increased from 0.25 mg/mL to 20 mg/mL. The improved SF microspheres, obtained by altering the distribution of molecular weight, have potential in drug and gene delivery applications. - Highlights: • MW distribution was changed by applying different dissolving methods of SF fiber. • Smaller and narrower MW distribution improves the quality of SF microspheres. • Size and polydispersity of microspheres increase as SF concentration increases. • Improved SF microspheres have potential in drug and gene delivery applications.

  19. Molecular weight and its distribution of tetrafluoroethylene and propylene copolymer

    Watanabe, Hiromasa; Okamoto, Jiro; Yamaguchi, Koichi.

    1978-04-01

    In comparison of molecular structure of tetrafluoroethylene and propylene copolymer produced by radiation and chemical initiators respectively, both were fractionated by elution method and fine structure was examined. For the fractionated sample by radiation, the relation between molecular weight anti Mn and intrinsic viscosity ( eta] is ( eta] = 3.97 x 10 -4 anti Mnsup(0.630) The result is not in agreement with that of the unfractionated sample by radiation, and similar to those of samples by chemical initiators. There is no difference, however, in the elution method of GPC between both these copolymers; the elution behavior agrees with that of standard polystyrene. Long chain branching thus exists little in the copolymer of tetrafluoroethylene and propylene. To reveal the relations between reaction conditions and molecular weight and its distribution of the copolymer produced by flow apparatus, the molecular weight distribution was measured by GPC. The method of analysis could evaluate molecular weight distribution changing constantly. (auth.)

  20. Influence of Hydroxypropyl Methylcellulose Molecular Weight Grade ...

    Erah

    weight grades (K4M and K15M) on drug release from diclofenac sodium matrix tablets. Methods: Tablets containing diclofenac ... Keywords: Matrix, Diclofenac sodium, HPMC, Erosion, Water uptake. Received: 12 January 2011 .... incorporating the structure and geometric characteristics of the release device and n is.

  1. Radiation chemistry of polymer degradation processes: molecular weight distribution effects

    Viswanathan, N.S.

    1976-01-01

    The molecular weight distributions of poly(methyl methacrylate) irradiated at 15 and 25 MeV with electron beams were investigated. The experimental values for the effect of chain scissions on the dispersivity agreed well with theoretical predictions

  2. Clinical effects of low-molecular-weight heparin combined with ...

    Tropical Journal of Pharmaceutical Research August 2016; 15 (8): 1787-1792 ... Keywords: Acute pancreatitis, Low-molecular-weight heparin, Multiple organ function syndrome,. APACHE II score ... mediators by lowering the expression of.

  3. High Molecular Weight Polymers in the New Chemicals Program

    There are three categories or types of High Molecular Weight (HMW, 10,000 daltons) polymers typically reviewed by the New Chemicals Program: Soluble, insoluble, and water absorbing. Each of the three types are treated differently.

  4. The Effect of Polymer Molecular Weight on Citrate Crosslinked ...

    Erah

    Purpose: To develop citrate crosslinked chitosan films using chitosan of different molecular weights. (MW) in .... left to stand until trapped air bubbles ... blotted out carefully with filter paper from the .... potential as biodegradable stent coatings. J.

  5. Low molecular weight salts combined with fluorinated solvents for electrolytes

    Tikhonov, Konstantin; Yip, Ka Ki; Lin, Tzu-Yuan; Lei, Norman; Guerrero-Zavala, Guillermo; Kwong, Kristie W.

    2015-11-10

    Provided are electrochemical cells and electrolytes used to build such cells. An electrolyte includes at least one salt having a molecular weight less than about 250. Such salts allow forming electrolytes with higher salt concentrations and ensure high conductivity and ion transport in these electrolytes. The low molecular weight salt may have a concentration of at least about 0.5M and may be combined with one or more other salts, such as linear and cyclic imide salts and/or methide salts. The concentration of these additional salts may be less than that of the low molecular weight salt, in some embodiments, twice less. The additional salts may have a molecular weight greater than about 250. The electrolyte may also include one or more fluorinated solvents and may be capable of maintaining single phase solutions at between about -30.degree. C. to about 80.degree. C.

  6. Isolation, Characterization and Molecular weight determination of ...

    Enzyme purification to homogeneity was carried out by anion exchange chromatography on DEAE-Sepharose. SDS-PAGE revealed molecular mass of 87 kDa. Maximal activity of the enzymes was observed at 50°C at pH 4 and was stimulated by Ca2+, Co2+, Mg2+ (test at 10 Mm each) and inhibited by Fe2+. Ethanol at an ...

  7. How does the preparation of rye porridge affect molecular weight distribution of extractable dietary fibers?

    Rakha, Allah; Aman, Per; Andersson, Roger

    2011-01-01

    Extractable dietary fiber (DF) plays an important role in nutrition. This study on porridge making with whole grain rye investigated the effect of rest time of flour slurries at room temperature before cooking and amount of flour and salt in the recipe on the content of DF components and molecular weight distribution of extractable fructan, mixed linkage (1→3)(1→4)-β-d-glucan (β-glucan) and arabinoxylan (AX) in the porridge. The content of total DF was increased (from about 20% to 23% of dry matter) during porridge making due to formation of insoluble resistant starch. A small but significant increase in the extractability of β-glucan (P = 0.016) and AX (P = 0.002) due to rest time was also noted. The molecular weight of extractable fructan and AX remained stable during porridge making. However, incubation of the rye flour slurries at increased temperature resulted in a significant decrease in extractable AX molecular weight. The molecular weight of extractable β-glucan decreased greatly during a rest time before cooking, most likely by the action of endogenous enzymes. The amount of salt and flour used in the recipe had small but significant effects on the molecular weight of β-glucan. These results show that whole grain rye porridge made without a rest time before cooking contains extractable DF components maintaining high molecular weights. High molecular weight is most likely of nutritional importance.

  8. How Does the Preparation of Rye Porridge Affect Molecular Weight Distribution of Extractable Dietary Fibers?

    Roger Andersson

    2011-05-01

    Full Text Available Extractable dietary fiber (DF plays an important role in nutrition. This study on porridge making with whole grain rye investigated the effect of rest time of flour slurries at room temperature before cooking and amount of flour and salt in the recipe on the content of DF components and molecular weight distribution of extractable fructan, mixed linkage (1→3(1→4-β-D-glucan (β-glucan and arabinoxylan (AX in the porridge. The content of total DF was increased (from about 20% to 23% of dry matter during porridge making due to formation of insoluble resistant starch. A small but significant increase in the extractability of β-glucan (P = 0.016 and AX (P = 0.002 due to rest time was also noted. The molecular weight of extractable fructan and AX remained stable during porridge making. However, incubation of the rye flour slurries at increased temperature resulted in a significant decrease in extractable AX molecular weight. The molecular weight of extractable β-glucan decreased greatly during a rest time before cooking, most likely by the action of endogenous enzymes. The amount of salt and flour used in the recipe had small but significant effects on the molecular weight of β-glucan. These results show that whole grain rye porridge made without a rest time before cooking contains extractable DF components maintaining high molecular weights. High molecular weight is most likely of nutritional importance.

  9. Application of radiation grafting techniques to prepare the high molecular weight water-soluble polymer

    Le Hai; Nguyen Quoc Hien; Nguyen Tan Man; Truong Thi Hanh; Le Huu Tu; Tran Thi Tam; Pham Thi Sam; Pham Anh Tuan; Le Dinh Lang

    2003-01-01

    The results of the study on the preparation of the high molecular weight water-soluble polymers by radiation grafting and their properties is presented as follows: 1/ by radiation grafting, the molecular weight of PVA was increased 20 times and PAM was increased only 3 times; 2/ the thermal and medium stability of poly(vinyl alcohol) grafted with acrylamide was obviously improved. (LH)

  10. Molecular weight kinetics and chain scission models for dextran polymers during ultrasonic degradation.

    Pu, Yuanyuan; Zou, Qingsong; Hou, Dianzhi; Zhang, Yiping; Chen, Shan

    2017-01-20

    Ultrasonic degradation of six dextran samples with different initial molecular weights (IMW) has been performed to investigate the degradation behavior and chain scission mechanism of dextrans. The weight-average molecular weight (Mw) and polydispersity index (D value) were monitored by High Performance Gel Permeation Chromatography (HPGPC). Results showed that Mw and D value decreased with increasing ultrasonic time, resulting in a more homologous dextran solution with lower molecular weight. A significant degradation occurred in dextrans with higher IMW, particularly at the initial stage of the ultrasonic treatment. The Malhotra model was found to well describe the molecular weight kinetics for all dextran samples. Experimental data was fitted into two chain scission models to study dextran chain scission mechanism and the model performance was compared. Results indicated that the midpoint scission model agreed well with experimental results, with a linear regression factor of R 2 >0.99. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Sintering of ultra high molecular weight polyethylene

    Unknown

    coefficient of friction, good abrasion resistance, good chemical resistance etc. It is used in ... mainly used in electrical industries, shipbuilding, coal and mining, textile ... particles deformed leading to decrease in porosity and increase in density.

  12. Virus Infection Triggers MAVS Polymers of Distinct Molecular Weight

    Natalia Zamorano Cuervo

    2018-01-01

    Full Text Available The mitochondrial antiviral signaling (MAVS adaptor protein is a central signaling hub required for cells to mount an antiviral response following virus sensing by retinoic acid-inducible gene I (RIG-I-like receptors. MAVS localizes in the membrane of mitochondria and peroxisomes and in mitochondrial-associated endoplasmic reticulum membranes. Structural and functional studies have revealed that MAVS activity relies on the formation of functional high molecular weight prion-like aggregates. The formation of protein aggregates typically relies on a dynamic transition between oligomerization and aggregation states. The existence of intermediate state(s of MAVS polymers, other than aggregates, has not yet been documented. Here, we used a combination of non-reducing SDS-PAGE and semi-denaturing detergent agarose gel electrophoresis (SDD-AGE to resolve whole cell extract preparations to distinguish MAVS polymerization states. While SDD-AGE analysis of whole cell extracts revealed the formation of previously described high molecular weight prion-like aggregates upon constitutively active RIG-I ectopic expression and virus infection, non-reducing SDS-PAGE allowed us to demonstrate the induction of lower molecular weight oligomers. Cleavage of MAVS using the NS3/4A protease revealed that anchoring to intracellular membranes is required for the appropriate polymerization into active high molecular weight aggregates. Altogether, our data suggest that RIG-I-dependent MAVS activation involves the coexistence of MAVS polymers with distinct molecular weights.

  13. Removal of high-molecular weight polycyclic aromatic hydrocarbons

    Ulrich Vasconcelos

    2011-01-01

    Full Text Available Alternatives for the removal of high-molecular weight polycyclic aromatic hydrocarbons (HWM-PAH from soil were tested by adding fertilizer or glycerol, as well as the combination of both. Experiments were carried out for 60 days in reactors containing a HWM-PAH-contaminated soil (8030 μg kg-1, accompanied by pH monitoring, humidity control and quantification of total heterotrophic bacteria and total fungus. Fertilizer addition removed 41.6% of HWM-PAH. Fertilizer and glycerol in combination removed 46.2%. When glycerol was added individually, degradation reached 50.4%. Glycerol also promoted the increase of degradation rate during the first 30 days suggesting the HMW-PAH removal occurred through cometabolic pathways.

  14. Should Low Molecular Weight PSMA Targeted Ligands Get Bigger and Use Albumin Ligands for PSMA Targeting?

    Huang, Steve S.; Heston, Warren D.W.

    2017-01-01

    Prostate Specific Membrane Antigen (PSMA) is strongly expressed in prostate cancer. Recently a number of low-molecular-weight inhibitors have demonstrated excellent PSMA targeting activity for both imaging as well as Lutecium-177 radiotherapy in human trials. The paper by Choy et al raises the question of whether we can further increase the effectiveness of PSMA targeted therapy by adding an albumin-binding entity to low-molecular-weight agents

  15. The molecular characterization of weighted Hardy spaces

    LI; Xingmin

    2001-01-01

    Surveys, 1993, 7: 305.[16]Shephand, N., Statistical aspects of ARCH and stochastic volatility, in Time Series Models in Econometrics, Finance and Other Fields (eds. Cox, D. R., Hinkley, D. V., Barndorff-Nielsen, O. E.), London: Chapman & Hall, 1996, 1.[17]Pantula, S. G., Estimation of autoregressive models with ARCH errors, Sankhya, Ser. B, 1988, 50: 119.[18]Campbell, J. Y., Lo, A. W., Mackinlay, A. C., The Econometrics of Financial Markets, Princeton: Princeton University Press, 1997, 488.[19]Fan, J., Gijbels, I., Local Polynomial Modeling and Its Applications, London: Chapman & Hall, 1996.[20]Lu, Z. D., A note on geometric ergodicity of autoregressive conditional heteroscedasticity (ARCH) model, Statistics and Probability Letters, 1996, 30: 305.[21]Robinson, P. M., Nonparametric estimators for time series, Journal of Time Series Analysis, 1983, 4: 185.[22]Stone, C. J., Optimal rates of convergence for nonparametric estimators, Annals of Statistics, 1980, 8: 1348.[23]Stone, C. J., Optimal global rates of convergence for nonparametric kernel regression, Annals of Statistics, 1982, 10: 1040.[24]Truong, Y. M., Stone, C. J., Nonparametric function estimation involving time series, Annals of Statistics, 1992, 20: 77.[25]Masry, E., Multivariate polynomial regression for time series; uniform strong consistency and rates, Journal of Time Series Analysis, 1996, 17: 571.[26]Ruppert, D., Wand, M. P., Multivariate locally weighted least squares regression, Annals of Statistics, 1994, 22: 1346.[27]Bollerslev, T., Generalized autoregressive conditional heteroscedasticity, Journal of Econometrics, 1986, 31: 307.[28]Engle, R. F., Granger, C. W. J., Co-integration and error-correction: representation, estimation and testing, Econometrica, 1987, 55: 251.

  16. In vitro anticoagulation monitoring of low-molecular-weight heparin

    WANG Jian-qi; SHI Xu-bo; YANG Jin-gang; HU Da-yi

    2009-01-01

    Background Although low-molecular-weight heparin has replaced unfractionated heparin to become the primary anticoagulation drug for treatment of acute coronary syndrome, there is no convenient bedside monitoring method. We explored the best laboratory monitoring method of low-molecular-weight heparins (enoxapadn, dalteparin, and nadroparin) by use of the Sonoclot coagulation analyzer to monitor the activated clotting time.Methods Atotal of 20 healthy volunteers were selected and 15 ml of fasting venous blood samples were collected and incubated. Four coagulants, kaolin, diatomite, glass bead, and magnetic stick, were used to determine the activated clotting time of the low-molecular-weight heparins at different in vitro anti-Xa factor concentrations. A correlation analysis was made to obtain the regression equation. The activated clotting time of the different low-molecular-weight heparins with the same anti-Xa factor concentration was monitored when the coagulant glass beads were applied. Results The activated clotting time measured using the glass beads, diatomite, kaolin, and magnetic stick showed a linear correlation with the concentration of nadroparin (r= 0.964, 0.966, 0.970, and 0.947, respectively). The regression equation showed that the linear slopes of different coagulants were significantly different (glass beads 230.03 s/IU,diatomite 89.91 s/IU, kaolin 50.87 s/IU, magnetic stick could not be calculated). When the concentration of the anti-Xa factor was the same for different low-molecular-weight heparins, the measured activated clotting time was different after the application of the glass bead coagulant.Conclusions The glass bead coagulant is most feasible for monitoring the in vitro anticoagulation activity of nadroparin.The different effects of different low-molecular-weight heparins on the activated clotting time may be related to the different anti-Ila activities.

  17. Development of radiation-resisting high molecular-weight materials

    Nakagawa, Tsutomu

    1976-01-01

    The excellent radiation-resisting polyvinyl chloride developed at the opportunity of the research on the relationships between the protection of living body and the polymer-technological protection from radiation is reviewed. The report is divided into four main parts, namely 1) the change in the molecular arrangement of market-available, high molecular-weight materials by gamma-ray irradiation, 2) the protection of high molecular-weight materials from radiation, 3) the relationships between the biological radiation-protective substances and the change to radiation-resisting property of synthesized high molecular-weight substances, and 4) the development of the radiation-resisting high molecular-weight materials as metal-collecting agents. Attention is paid to the polyvinyl chloride having N-methyl-dithio-carbamate radical (PMD), synthesized by the author et. al., that has excellent radiation-resisting property. PMD has some possibility to form thiol- and amino-radicals necessary to protect living things from radiation. It is believed that the protection effects of N-methyl-dithio-carbamate radical are caused by the relatively stable S radical produced by the energy transfer. PMD film is suitable for the irradiation of foods, because it hardly changes the permeability of oxygen and carbon dioxide. PMD produces mercaptide or chelate. A new metal-collecting agent (PSDC) having reactivity with the metallic ions with radiation-resisting property was developed, which is derived from polyvinyl chloride and sodium N-methyl-N-carboxy-methyl-dithio-carbamate. (Iwakiri, K.)

  18. Molecular weight enlargement : a molecular approach to continuous homogeneous catalysis

    Janssen, M.C.C.

    2010-01-01

    Homogeneous catalysts play an increasingly important role in organic synthesis today, because of their high activity and selectivity. Usually, precious metals are used in combination with valuable ligands and since metal prices are expected to increase further in the future, methods for their

  19. Early weight changes after birth and serum high-molecular-weight adiponectin level in preterm infants.

    Yoshida, Tomohide; Nagasaki, Hiraku; Asato, Yoshihide; Ohta, Takao

    2011-12-01

    Extra-uterine growth retardation (EUGR) is associated with an increased risk for cardiometabolic diseases later in life. The aim of the present study was to examine the relationship between early weight change after birth in preterm infants and adiponectin (adn) multimeric complexes. Subjects included 28 preterm infants born between weeks 24 and 33 of gestation. Serum adn multimeric complexes and the anthropometric parameters were measured in preterm infants at birth and at corrected term. Bodyweight (BW) decreased during the first week of life, with birthweight restored at approximately 19 days after birth. Nineteen of the subjects had EUGR at corrected term. Total (T)-adn, high-molecular-weight (H)-adn, and the ratio of H-adn to T-adn (H/T-adn) were significantly elevated at corrected term than at birth. Postmenstrual age, birthweight, birth length and lowest BW after birth were positively correlated with H-adn and H/T-adn. Weight reduction after birth was negatively correlated with H-adn. Age to restore birthweight was negatively correlated with T-adn, H-adn and H/T-adn. Stepwise multiple regression analysis indicated age to restore birthweight as the major predictor of T-adn and H-adn. Early weight changes after birth may alter serum adn level in preterm infants at corrected term. The appropriate nutritional support in the early postnatal period could reduce the prevalence of EUGR and the future risk for cardiometabolic diseases. © 2011 The Authors. Pediatrics International © 2011 Japan Pediatric Society.

  20. When weight management lasts. Lower perceived rule complexity increases adherence.

    Mata, Jutta; Todd, Peter M; Lippke, Sonia

    2010-02-01

    Maintaining behavior change is one of the major challenges in weight management and long-term weight loss. We investigated the impact of the cognitive complexity of eating rules on adherence to weight management programs. We studied whether popular weight management programs can fail if participants find the rules too complicated from a cognitive perspective, meaning that individuals are not able to recall or process all required information for deciding what to eat. The impact on program adherence of participants' perceptions of eating rule complexity and other behavioral factors known to influence adherence (including previous weight management, self-efficacy, and planning) was assessed via a longitudinal online questionnaire given to 390 participants on two different popular weight management regimens. As we show, the regimens, Weight Watchers and a popular German recipe diet (Brigitte), strongly differ in objective rule complexity and thus their cognitive demands on the dieter. Perceived rule complexity was the strongest factor associated with increased risk of quitting the cognitively demanding weight management program (Weight Watchers); it was not related to adherence length for the low cognitive demand program (Brigitte). Higher self-efficacy generally helped in maintaining a program. The results emphasize the importance of considering rule complexity to promote long-term weight management. 2009 Elsevier Ltd. All rights reserved.

  1. Control of molecular weight distribution in synthesis of poly(2-hydroxyethyl methacrylate) using ultrasonic irradiation.

    Kubo, Masaki; Kondo, Takayuki; Matsui, Hideki; Shibasaki-Kitakawa, Naomi; Yonemoto, Toshikuni

    2018-01-01

    Poly(2-hydroxyethyl methacrylate) (PHEMA) was synthesized using ultrasonic irradiation without any chemical initiator. The effect of the ultrasonic power intensity on the time course of the conversion to polymer, the number average molecular weight, and the polydispersity were investigated in order to synthesize a polymer with a low molecular weight distribution (i.e., low polydispersity). The conversion to polymer increased with time. A higher ultrasonic power intensity resulted in a faster reaction rate. The number average molecular weight increased during the early stage of the reaction and then gradually decreased with time. A higher ultrasonic intensity resulted in a faster degradation rate of the polymer. The polydispersity decreased with time. This was because the degradation rate of a polymer with a higher molecular weight was faster than that of a polymer with a lower molecular weight. A polydispersity below 1.3 was obtained under ultrasonic irradiation. By changing the ultrasonic power intensity during the reaction, the number average molecular weight can be controlled while maintaining low polydispersity. When the ultrasonic irradiation was halted, the reactions stopped and the number average molecular weight and polydispersity did not change. On the basis of the experimental results, a kinetic model for synthesis of PHEMA under ultrasonic irradiation was constructed considering both polymerization and polymer degradation. The kinetic model was in good agreement with the experimental results for the time courses of the conversion to polymer, the number average molecular weight, and the polydispersity for various ultrasonic power intensities. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Low Molecular Weight Z-Tetraol Boundary Lubricant Films in Hard Disk Drives

    R. J. Waltman

    2012-01-01

    Full Text Available Lower molecular weight Z-Tetraol films exhibit increased mechanical spacing in the slider-disk interface due to a lower z-profile. An increased resistance to lubricant disturbance on the disk surface (e.g., lube moguls with decreasing film thickness is attributed to an increasing contribution from the polar component of the disjoining pressure. Evaporative loss at temperatures typically encountered in a hard-disk drive also increases with decreasing molecular weight but is strongly dependent on the initial bonded fraction.

  3. Influence of polymer additive molecular weight on surface and ...

    2, April 2011, pp. 347–356. c Indian Academy of Sciences. Influence of polymer additive molecular weight on surface and microstructural characteristics of electrodeposited copper. R MANU. ∗ and SOBHA JAYAKRISHNAN. Electroplating and Metal Finishing Technology Division, Central Electrochemical Research Institute,.

  4. High Molecular Weight Polybenzimidazole Membranes for High Temperature PEMFC

    Yang, Jingshuai; Cleemann, Lars Nilausen; Steenberg, T.

    2014-01-01

    High temperature operation of proton exchange membrane fuel cells under ambient pressure has been achieved by using phosphoric acid doped polybenzimidazole (PBI) membranes. To optimize the membrane and fuel cells, high performance polymers were synthesized of molecular weights from 30 to 94 kDa w...

  5. Low-molecular-weight chitosans: Preparation and characterization

    Tishchenko, Galina; Šimůnek, Jiří; Brus, Jiří; Netopilík, Miloš; Pekárek, Michal; Walterová, Zuzana; Koppová, Ingrid; Lenfeld, Jiří

    2011-01-01

    Roč. 86, č. 2 (2011), s. 1077-1081 ISSN 0144-8617 R&D Projects: GA ČR(CZ) GA525/08/0803 Institutional research plan: CEZ:AV0Z40500505; CEZ:AV0Z50450515 Keywords : low-molecular-weight chitosans * chitooligosaccharides * oxidative depolymerization Subject RIV: ED - Physiology Impact factor: 3.628, year: 2011

  6. molecular weight control of a batch suspension polymerization reactor

    Shahrokhi, M.; Fanaei, M. A.

    2002-01-01

    This paper concerns molecular weight control of a batch polymerization reactor where suspension polymerization of methyl methylacrylate (MMA) takes place. For this purpose, a cascade control structure with two control loops has been selected. The slave loop is used for temperature control using on-line temperature measurements, and the master loop controls the average molecular weights based on its estimated values. Two different control algorithms namely proportional-integral (PI) controller and globally linearizing controller (GLC) have been used for temperature control. An estimator, which has the structure of an extended Kalman filter(EKF), is used for estimating monomer conversion and average molecular weights of polymer using reactor temperature measurements. The performance of proposed control algorithm is evaluated through simulation and experimental studies. The results indicate that a constant average molecular weight cannot be achieved in case of strong gel effect. However, the polydispersity of product will be lower in comparison to isothermal operation. It is also shown that in case of mo dek mismatch, the performance of cascade control is superior compared to the case where only reactor temperature is controlled based on desired temperature trajectory obtained through cascade strategy

  7. Electrophoretic behavior in filter paper and molecular weight of insulin

    Sluyterman, L.A.A.E.

    1955-01-01

    Insulin travels as well defined band in electropherograms if acetic acid-water 1:2 (v/v) is used as a buffer. Preparations of partially acetylated insulin were analysed by this method. From the results it could be derived that the molecular weight of insulin is 6,000. An improvement in the

  8. Clinical effects of low-molecular-weight heparin combined with ...

    Purpose: To explore the clinical effects of low-molecular-weight heparin (LMWH) combined with ulinastatin (UTI) in children with acute pancreatitis. Methods: In total, 560 patients with severe acute pancreatitis treated at Binzhou People's Hospital, Shandong, China, from April 2012 to June 2014 were enrolled in this study.

  9. Antiaging activity of low molecular weight peptide from Paphia undulate

    Chen, Xin; Cai, Bingna; Chen, Hua; Pan, Jianyu; Chen, Deke; Sun, Huili

    2013-05-01

    Low molecular weight peptide (LMWP) was prepared from clam Paphia undulate and its antiaging effect on D-galactose-induced acute aging in rats, aged Kunming mice, ultraviolet-exposed rats, and thermally injured rats was investigated. P. undulate flesh was homogenized and digested using papain under optimal conditions, then subjected to Sephadex G-25 chromatography to isolate the LMWP. Administration of LMWP significantly reversed D-galactose-induced oxidative stress by increasing the activities of glutathione peroxidase (GPx) and catalase (CAT), and by decreasing the level of malondialdehyde (MDA). This process was accompanied by increased collagen synthesis. The LMWP prevented photoaging and promoted dermis recovery and remission of elastic fiber hyperplasia. Furthermore, treatment with the LMWP helped to regenerate elastic fibers and the collagen network, increased superoxide dismutase (SOD) in the serum and significantly decreased MDA. Thermal scald-induced inflammation and edema were also relieved by the LWMP, while wound healing in skin was promoted. These results suggest that the LMWP from P. undulate could serve as a new antiaging substance in cosmetics.

  10. Western blotting of high and low molecular weight proteins using heat.

    Kurien, Biji T; Scofield, R Hal

    2015-01-01

    A method for the electrophoretic transfer of high and low molecular weight proteins to nitrocellulose membranes following sodium dodecyl sulfate (SDS) polyacrylamide gel is described here. The transfer was performed with heated (70-75 °C) normal transfer buffer from which methanol had been omitted. Complete transfer of high and low molecular weight antigens (molecular weight protein standards, a purified protein, and proteins from a human tissue extract) could be carried out in 10 min for a 7 % (0.75 mm) SDS polyacrylamide gel. For 10 and 12.5 % gels (0.75 mm) the corresponding time was 15 min. A complete transfer could be carried out in 20 min for 7, 10, and 12.5 % gels (1.5 mm gels). The permeability of the gel is increased by heat, such that the proteins trapped in the polyacrylamide gel matrix can be easily transferred to the membrane. The heat mediated transfer method was compared with a conventional transfer protocol, under similar conditions. The conventional method transferred minimal low molecular weight proteins while retaining most of the high molecular weight proteins in the gel. In summary, this procedure is particularly useful for the transfer of high molecular weight proteins, very rapid, and avoids the use of methanol.

  11. Effect of molecular weight on the quality of poly(alpha-methylstyrene mandrel

    Xiuyun Shangguan

    2017-07-01

    Full Text Available Hollow poly(alpha-methylstyrene (PAMS shows application in inertial confinement fusion experiments as the degradable mandrels of glow plasma polymer shells. However, the molecular weight of PAMS has great influence on the quality of mandrels. In this work, this influence was systematically studied using several PAMS samples with different molecular weights. For PAMS shells with 900 μm inner diameter and different wall thickness, when the molecular weight of PAMS is in the range of 300–500 kg·mol−1, perfect sphericity and good wall thickness uniformity can be obtained. In contrast, when increasing molecular weight to 800 kg·mol−1, the sphericity and the wall thickness uniformity become worse. Moreover, compared with the wall uniformity, the sphericity of PAMS shells was much less sensitive to the molecular weight. The results also showed that the stability of W1/O compound droplets of PAMS shells were less affected by the molecular weight. It was revealed that the wall uniformity and the sphericity of the PAMS shells were associated with the diffusion rates of fluorobenzene (FB.

  12. Practical γ-Ray Level for Low Molecular Weight Chitosan

    Yoksan, Rangrong; Chirachanchai, Suwabun; Biramontri, Siriratana

    2003-06-01

    The present work proposes a practical level of γ-Ray to lower the molecular weigh of chitosan irradiated in solid state and water. The molecular weight reduction is up to 80% at γ-ray amount of 50 kGy. The same level of reduction can be achieved by only 20 kGy in the presence of initiator (K 2 S 2 O 8 or H 2 O 2 ). The structure is significantly changed in the case of chitosan-acetic acid solution or chitosan dispersed in water with 2% aq. K 2 S 2 O 8 solution

  13. The Effect of Low Molecular Weight Heparins on Fracture Healing.

    Kapetanakis, Stylianos; Nastoulis, Evangelos; Demesticha, Theano; Demetriou, Thespis

    2015-01-01

    Venous Thromboembolism is a serious complication in the trauma patient. The most commonly studied and used anticoagulant treatment in prophylaxis of thrombosis is heparin. The prolonged use of unfractionated heparin has been connected with increased incidence of osteoporotic fractures. Low molecular-weight-heparins (LMWHs) have been the golden rule in antithrombotic therapy during the previous two decades as a way to overcome the major drawbacks of unfractioned heparin. However there are few studies reporting the effects of LMWHs on bone repair after fractures. This review presents the studies about the effects of LMWHs on bone biology (bone cells and bone metabolism) and underlying the mechanisms by which LMWHs may impair fracture healing process. The authors' research based on literature concluded that there are no facts and statistics for the role of LMWHs on fracture healing process in humans and the main body of evidence of their role comes from in vitro and animal studies. Further large clinical studies designed to compare different types of LMWHs, in different dosages and in different patient or animal models are needed for exploring the effects of LMWHs on fracture healing process.

  14. The distribution of 14C-chitosan by different molecular weight in mice

    Kim, Kwang Yoon; Kim, Young Ho; Bom, Hee Seung; Kim, Ji Yeul; Kim, Hee Kyung; Roh, Young Bok; Nishimura, Yoshikazu

    1998-01-01

    Chitosan is a nontoxic natural chealtor which was made by chitin, and reduced a contamination of radiostrontium in animals. In this experiment, a different molecular weight of C-14 chitosan was intravenously administered to mice, and then the distribution of C-14 chitosan in the body was observed. Male mice (8 to 10 weeks, body weight of 30 to 35g) of ICR strain were used. C-14 chitosan, mice was sacrificed at the 6th hour, 1st, 3rd, 5th, and 7th day. Beta radioactivities in the blood, liver, kidney, liver, muscle, testis, and urine was measured using a liquid scintillation analyzer. Most of the C-14 chitosan was excreted through urine within 6 hours. Biodistribution of C-14 chitosan was similar despite the difference of molecular weight. Higher distributions of radioactivities were found in the liver, kidney, spleen. The relative concentration in tissue increased for the 6 hours and then decreased. In conclusion, most of C-14 chitosan was excreted through urine despite the difference of molecular weight. and, low molecular weight of C-14 chitosan showed higher distribution than high molecular weight of C-14 chitosan in tissues

  15. The influence of molecular weight in radiotracers of inflamators processes

    Mesa Duennas, N.; Zayas Crespo, F.; Piedra Mazorra, J.; Diaz Barreto, M; Rodriguez Alfonso, M.E.; Perez Fuentes, A.

    2004-01-01

    Four 99mTc-radiopharmaceuticals (RPs) were compared as a radiotracers of inflammatory process. The RPs were divided in two groups according to their molecular weights and nature. One group included the human IgG and the ior t3 MoAb (anti-CD3), another included the Ciprofloxacine and the DMSA. The RPs were studied by different quality controls, and a biodistribution study in an aseptic inflammatory model made by steril Carragenin. The results obtained in the reduction of the immunoglobulins with 2-mercaptoethanol and sodium metabisulphite demonstrated that both reducing agents were equivalent, because the radiochemical purity obtained were similar and independent of the immunoglobulins. The biodistribution demonstrated a higher incorporation for the radiopharmaceuticals of high molecular weight, and the highest values were obtained with the 2-mercaptoethanol

  16. Solvent extraction of cerium (III) with high molecular weight amines

    Chatterjee, A.; Basu, S.

    1992-01-01

    The use of high molecular weight amines in the extraction of cerium (III) as EDTA complex from neutral aqueous medium is reported. The extraction condition was optimised from the study of effects of several variables like concentration of amine and EDTA pH nature of diluents etc. The method has been applied for the determination of cerium in few mineral samples. (author). 7 refs., 5 tabs

  17. High molecular weight polysaccharide that binds and inhibits virus

    Konowalchuk, Thomas W

    2014-01-14

    This invention provides a high molecular weight polysaccharide capable of binding to and inhibiting virus and related pharmaceutical formulations and methods on inhibiting viral infectivity and/or pathogenicity, as well as immunogenic compositions. The invention further methods of inhibiting the growth of cancer cells and of ameliorating a symptom of aging. Additionally, the invention provides methods of detecting and/or quantifying and/or isolating viruses.

  18. Physical Properties of Low-Molecular Weight Polydimethylsiloxane Fluids

    Roberts, Christine Cardinal [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Graham, Alan [Univ. of Colorado, Denver, CO (United States); Nemer, Martin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Phinney, Leslie M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Garcia, Robert M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Soehnel, Melissa Marie [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Stirrup, Emily Kate [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-02-01

    Physical property measurements including viscosity, density, thermal conductivity, and heat capacity of low-molecular weight polydimethylsiloxane (PDMS) fluids were measured over a wide temperature range (-50°C to 150°C when possible). Properties of blends of 1 cSt and 20 cSt PDMS fluids were also investigated. Uncertainties in the measurements are cited. These measurements will provide greater fidelity predictions of environmental sensing device behavior in hot and cold environments.

  19. High molecular weight polysaccharide that binds and inhibits virus

    Konowalchuk, Thomas W.; Konowalchuk, Jack

    2017-07-18

    This invention provides a high molecular weight polysaccharide capable of binding to and inhibiting virus and related pharmaceutical formulations and methods of inhibiting viral infectivity and/or pathogenicity, as well as immunogenic compositions. The invention further includes methods of inhibiting the growth of cancer cells and of ameliorating a symptom of aging. Additionally, the invention provides methods of detecting and/or quantifying and/or isolating viruses.

  20. Steroidogenic activity of high molecular weight forms of ACTH

    Gasson, J.C.

    1979-01-01

    The relative steroidogenic potencies of high molecular weight forms of adrenocorticotropic hormone (ACTH) were investigated using in vitro bioassays. In order to prepare pools of separated pro-ACTH/endorphin, ACTH biosynthetic intermediate and glycosylated ACTH (1-39), the protein present in serum-free tissue culture medium obtained from cultured AtT-20/D-16v mouse pituitary tumor cells was concentrated and fractionated by gel filtration. Based on sodium dodecyl sulfate polyacrylamide gel electrophoresis, over 97% of the immunoactive ACTH in each pool had the appropriate molecular weight. Suspensions of isolated rat and guinea pig adrenal cortical cells were prepared by enzymatic dissociation and mechanical dispersion. Cells were incubated in complete tissue culture medium overnight then used in a 2 hour steroid production assay. Synthetic hACTH(1-39) was used as a bioassay and immunoassay standard. The amounts of pro-ACTH/endorphin, ACTH biosynthetic intermediate and glycosylated ACTH(1-39) bioassayed were estimated by ACTH(17-24) radioimmunoassay. All three high molecular weight forms of ACTH were capable of stimulating the same maximal level of steroidogenesis, by both isolated rat and guinea pig adrenal cells, as hACTH(1-39). Glycosylated ACTH(1-39) was equipotent with hACTH(1-39); pro-ACTH/endorphin and ACTH biosynthetic intermediate were two orders of magnitude less potent than hACTH(1-39) in both bioassay systems

  1. Media optimization for elevated molecular weight and mass production of pigment-free pullulan.

    Yu, Xiaoliu; Wang, Yulei; Wei, Gongyuan; Dong, Yingying

    2012-07-01

    In this study, an Aureobasidium pullulans SZU 1001 mutant, deficient in pigment production, was screened by complex UV and γ-ray mutagenesis. Medium composition optimization for increased pullulan molecular weight and production was conducted using this mutant. Six nutrients: yeast extract, (NH4)2SO4, K2HPO4, NaCl, MgSO4·7H2O and CaCl2 were detected within pullulan production in flasks. It is shown that NaCl and K2HPO4 have significant influences on molecular weight of pullulan, while yeast extract and (NH4)2SO4 significantly affect pullulan yield. To achieve a higher molecular weight and more efficient pullulan production, a response surface methodology approach was introduced to predict an optimal nutrient combination. A molecular weight of 5.74 × 10(6) and pullulan yield on glucose of 51.30% were obtained under batch pullulan fermentation with the optimized media, which increased molecular weight and pullulan production by 97.25% and 11.04%, respectively compared with the control media. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Synthesis and properties of aqueous polyurethane dispersions: Influence of molecular weight of polyethylene glycol

    Mumtaz, Fatima; Zuber, Mohammad; Zia, Khalid Mahmood [Government College University, Faisalabad (Pakistan); Jamil, Tahir [University of the Punjab, Lahore (Pakistan); Hussain, Rizwan [National Engineering and Scientific Commission (NESCOM), Islamabad (Pakistan)

    2013-12-15

    Aqueous polyurethane dispersions (PUDs) have recently emerged as important alternatives to their solvent-based counterparts for various applications due to increasing health and environmental awareness. A series of aqueous polyurethane dispersions containing carboxylate anion as hydrophilic pendant groups were synthesized through step growth polymerization reaction using hexamethylene diisocyanate (HDI), 1,4-butanediol (1,4-BDO), dimethylol propionic acid (DMPA) and polyethylene glycol (PEG) of different molecular weight. Effect of PEG molecular weight was investigated on molecular structure, contact angle measurement, and physical and adhesive properties of PU emulsions. Fourier transform infrared spectroscopy (FT-IR) was used to check the completion of polymerization reaction. Contact angle measurement indicated that the hydrophilicity of polymer increases by increasing molecular weight of PEG with a corresponding decrease in contact angle. Results of T-peel test showed a decrease in peel strength by increasing molecular weight of PEG. Moreover, solid contents%, drying time and storage stability suggested fast drying properties and greater stability of aqueous PU dispersions.

  3. Emulsifier-free emulsion polymerization of tetrafluoroethylene by radiation. IV. Effects of additives on Polymer molecular weight

    Watanabe, T.; Suwa, T.; Okamoto, J.; Machi, S.

    1979-01-01

    Poly(tetrafluoroethylene)(PTFE) of high molecular weight, 4.5 x 10 7 , was incidentally obtained at earlier study of an emulsifier-free emulsion polymerization of tetrafluoroethylene by radiation. In order to clarify this phenomenon, the effects of additives, in particular radical scavengers, on the molecular weight of PTFE and its polymerization behavior were studied. It was found that the molecular weight of PTFE is increased by the addition of hydroquinone, benzoquinone, α-pinene, dl-limonene, and ethylenediamine but is decreased by oxygen and triethylamine. A PTFE latex with molecular weight higher than 2 x 10 7 was obtained in the presence of hydroquinone. It is concluded that additives such as hydroquinone and benzaquinone, which rapidly scavenge the primary radicals (OH, H, and e/sub aq/ - ) in the aqueous phase but not the growing polymer radicals in PTFE particles, are most effective in increasing the molecular weight

  4. Influence of psychotropic drugs prescription on body weight increase

    Blanca E. Martínez de Morentin-Aldabe

    2013-03-01

    Full Text Available Obesity has become a major public health burden, not only by the rising prevalence but also because of the associated complications. Furthermore there is a number of diseases whose risk and onset is increased in subjects with overweight such as type 2 diabetes, dislipemias, tumors (endometrial, colon, breast, cancer, etc, skeletal disorders, digestive disturbances, cardiovascular diseases, respiratory disorders, psychological problems, obstetric and gynecological disorders.The prescription of psychotropic drugs is important and, in most countries, consumption has been increased in recent years. Indeed, several drugs used in the treatment of anxiety, depression, bipolar disorder, schizophrenia or epilepsy, can increase body weight and fat deposition or eventually decrease it. These side effects could make a previous situation of obesity to worsen, and it can even cause excessive weight gain in patients with a normal weight at the beginning of the treatment. This increase in adiposity may also contribute to the lack of adherence to the medication and thus a possible relapse of the patients.In this review we report the links between psychotropic drugs administration and weight gain as well as the potential mechanisms that are involved.DOI: http://dx.doi.org/10.14306/renhyd.17.1.4

  5. Effect of various solvents on the viscosity-average molecular weight of poly (vinyl acetate)

    Rehman, W.U.; But, M.A.; Chughtai, A.; Jamil, T.; Sattar, A.

    2006-01-01

    Solution polymerization of Vinyl Acetate was carried out in various solvents (benzene, toluene, ethyl acetate, acetonitrile). Dilute solution viscometry was used to determine the viscosity-average molecular weight of the resulting Poly (Vinyl Acetate) (PV Ac) in each case. The viscosity-average molecular weight (M,J of PVAc was found to increase in the order benzene < toluene < ethyl acetate < acetonitrile, It was concluded that under the same reaction conditions (polymerization time, initiator quantity, solvent/monomer ratio, temperature), acetonitrile served as the best solvent for solution. polymerization of Vinyl Acetate monomer. (author)

  6. Cytotoxicity of polycations: Relationship of molecular weight and the hydrolytic theory of the mechanism of toxicity.

    Monnery, Bryn D; Wright, Michael; Cavill, Rachel; Hoogenboom, Richard; Shaunak, Sunil; Steinke, Joachim H G; Thanou, Maya

    2017-04-15

    The mechanism of polycation cytotoxicity and the relationship to polymer molecular weight is poorly understood. To gain an insight into this important phenomenon a range of newly synthesised uniform (near monodisperse) linear polyethylenimines, commercially available poly(l-lysine)s and two commonly used PEI-based transfectants (broad 22kDa linear and 25kDa branched) were tested for their cytotoxicity against the A549 human lung carcinoma cell line. Cell membrane damage assays (LDH release) and cell viability assays (MTT) showed a strong relationship to dose and polymer molecular weight, and increasing incubation times revealed that even supposedly "non-toxic" low molecular weight polymers still damage cell membranes. The newly proposed mechanism of cell membrane damage is acid catalysed hydrolysis of lipidic phosphoester bonds, which was supported by observations of the hydrolysis of DOPC liposomes. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  7. Ozonation of humic substances: Effects on molecular weight distributions of organic carbon and trihalomethane formation potential

    Amy, G.L.; Kuo, C.J.; Sierka, R.A.

    1988-01-01

    Four different sources of humic substances were studied to determine the effects of ozonation on molecular weight distributions, based on dissolved organic carbon (DOC) and trihalomethane formation potential (THMFP). Solutions of two soil-derived fulvic acids and a one soil-derived humic acid, as well as dissolved organic matter (DOM) associated with a natural water source were studied. Both gel permeation chromatography (GPC) and ultrafiltration (UF) were employed to define apparent molecular weight (AMW). Applied ozone doses ranged from 2.0 to 2.5 mg O 3 /mg DOC. Overall samples of untreated and ozonated waters, as well as individual molecular weight fractions, were characterized according to DOC, uv absorbance, and THMFP. Ozonation resulted in a significant disappearance of higher AMW material with a corresponding increase in lower AMW material. Although little overall reduction in DOC concentration was observed, significant overall reductions in UV absorbance and THMFP levels were observed

  8. Low Molecular Weight Chitosan–Insulin Polyelectrolyte Complex: Characterization and Stability Studies

    Zakieh I. Al-Kurdi

    2015-03-01

    Full Text Available The aim of the work reported herein was to investigate the effect of various low molecular weight chitosans (LMWCs on the stability of insulin using USP HPLC methods. Insulin was found to be stable in a polyelectrolyte complex (PEC consisting of insulin and LMWC in the presence of a Tris-buffer at pH 6.5. In the presence of LMWC, the stability of insulin increased with decreasing molecular weight of LMWC; 13 kDa LMWC was the most efficient molecular weight for enhancing the physical and chemical stability of insulin. Solubilization of insulin-LMWC polyelectrolyte complex (I-LMWC PEC in a reverse micelle (RM system, administered to diabetic rats, results in an oral delivery system for insulin with acceptable bioactivity.

  9. Thermal characterization of Ag and Ag + N ion implanted ultra-high molecular weight polyethylene (UHMWPE)

    Sokullu Urkac, E.; Oztarhan, A.; Tihminlioglu, F.; Kaya, N.; Ila, D.; Muntele, C.; Budak, S.; Oks, E.; Nikolaev, A.; Ezdesir, A.; Tek, Z.

    2007-08-01

    Most of total hip joints are composed of ultra-high molecular weight polyethylene (UHMWPE). However, as ultra-high molecular weight polyethylene is too stable in a body, wear debris may accumulate and cause biological response such as bone absorption and loosening of prosthesis. In this study, ultra-high molecular weight polyethylene samples were Ag and Ag + N hybrid ion implanted by using MEVVA ion implantation technique to improve its surface properties. Samples were implanted with a fluence of 1017 ion/cm2 and extraction voltage of 30 kV. Implanted and unimplanted samples were investigated by thermo-gravimetry analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), optical microscopy (OM) and contact Angle measurement. Thermal characterization results showed that the ion bombardment induced an increase in the % crystallinity, onset and termination degradation temperatures of UHMWPE.

  10. Thermal characterization of Ag and Ag + N ion implanted ultra-high molecular weight polyethylene (UHMWPE)

    Sokullu Urkac, E. [Department of Materials Science, Izmir High Technology Institute, Gulbahcekoyu Urla, Izmir (Turkey)]. E-mail: emelsu@gmail.com; Oztarhan, A. [Bioengineering Department, Ege University, Bornova, Izmir 35100 (Turkey); Tihminlioglu, F. [Department of Chemical Engineering, Izmir High Technology Institute, Gulbahcekoyu Urla, Izmir (Turkey); Kaya, N. [Bioengineering Department, Ege University, Bornova, Izmir 35100 (Turkey); Ila, D. [Center for Irradiation of Materials, Alabama A and M University, Normal AL 35762 (United States); Muntele, C. [Center for Irradiation of Materials, Alabama A and M University, Normal AL 35762 (United States); Budak, S. [Center for Irradiation of Materials, Alabama A and M University, Normal AL 35762 (United States); Oks, E. [H C Electronics Institute, Tomsk (Russian Federation); Nikolaev, A. [H C Electronics Institute, Tomsk (Russian Federation); Ezdesir, A. [R and D Department, PETKIM Holding A.S., Aliaga, Izmir 35801 (Turkey); Tek, Z. [Department of Physics, Celal Bayar University, Manisa (Turkey)

    2007-08-15

    Most of total hip joints are composed of ultra-high molecular weight polyethylene (UHMWPE ). However, as ultra-high molecular weight polyethylene is too stable in a body, wear debris may accumulate and cause biological response such as bone absorption and loosening of prosthesis. In this study, ultra-high molecular weight polyethylene samples were Ag and Ag + N hybrid ion implanted by using MEVVA ion implantation technique to improve its surface properties. Samples were implanted with a fluence of 10{sup 17} ion/cm{sup 2} and extraction voltage of 30 kV. Implanted and unimplanted samples were investigated by thermo-gravimetry analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), optical microscopy (OM) and contact Angle measurement. Thermal characterization results showed that the ion bombardment induced an increase in the % crystallinity, onset and termination degradation temperatures of UHMWPE.

  11. Low-molecular-weight heparins: pharmacologic profile and product differentiation.

    Fareed, J; Jeske, W; Hoppensteadt, D; Clarizio, R; Walenga, J M

    1998-09-10

    The interchangeability of low-molecular-weight heparins (LMWHs) has been the subject of discussion since these products were first introduced for the prophylaxis of deep vein thrombosis. Experimental evidence now exists to show that LMWHs differ from each other in a number of characteristics. Products have been differentiated on the basis of molecular weight and biologic properties, but only limited information derived from the clinical setting is available. Potency has been described on the basis of anti-Factor Xa activity, but at equivalent anti-Xa activities, the anti-Factor IIa activity of different products shows marked variations. At the relatively small doses used for the management of postsurgical deep vein thrombosis, the effect of these interproduct differences may be relatively minor, but as LMWHs are developed for therapeutic use at much higher doses, such differences may become clinically important. Variations in safety and efficacy reported in clinical trials of LMWHs may reflect the known differences in their molecular composition and pharmacologic properties.

  12. An evaluation of the effects of PEO/PEG molecular weights on extruded alumina rods

    Bolger, Nancy Beth

    1998-12-01

    the changing additions. Polyethylene oxide, in combination with polyethylene glycol, did show an increase in green strength versus the polyethylene oxide alone. Strengths were still lower than those displayed by the polyethylene glycols alone. Reductions or degradations in molecular weight of the polymers due to mixing and extrusion processes may account for lower green strength of bodies, especially those containing polyethylene oxides.

  13. Low molecular weight chemical-induced occupational asthma : The focus on alveolar macrophages

    Valstar, Dingena Labine

    2004-01-01

    Asthma is a very common disorder and its prevalence has increased over the past two to three decades. The proportion of cases attributable to occupational exposure at the workplace is estimated at ~10% of adult-onset asthma. Most cases of occupational asthma are caused by low molecular weight

  14. Preoperative weight gain might increase risk of gastric bypass surgery.

    Istfan, Nawfal W; Anderson, Wendy A; Apovian, Caroline M; Hess, Donald T; Forse, R Armour

    2011-01-01

    Weight loss improves the cardiovascular and metabolic risk associated with obesity. However, insufficient data are available about the health effects of weight gain, separate from the obesity itself. We sought to determine whether the changes in body weight before open gastric bypass surgery (OGB) would have a significant effect on the immediate perioperative hospital course. A retrospective chart review of 100 consecutive patients was performed to examine the effects of co-morbidities and body weight changes in the immediate preoperative period on the hospital length of stay and the rate of admission to the surgical intensive care unit (SICU). Of our class III obese patients undergoing OGB, 95% had ≥1 co-morbid condition and an overall SICU admission rate of 18%. Compared with the patients with no perioperative SICU admission, the patients admitted to the SICU had a greater degree of insulin resistance (homeostatic model analysis-insulin resistance 10.8 ± 1.3 versus 5.9 ± 0.5, P = .001), greater serum triglyceride levels (225 ± 47 versus 143 ± 8 mg/dL, P = .003), and had gained more weight preoperatively (.52 ± .13 versus .06 ± .06 lb/wk, P = .003). The multivariate analyses showed that preoperative weight gain was a risk factor for a longer length of stay and more SICU admissions lasting ≥3 days, as were a diagnosis of sleep apnea and an elevated serum triglyceride concentration. The results of the present retrospective study suggest that weight gain increases the risk of perioperative SICU admission associated with OGB, independent of the body mass index. Sleep apnea and elevated serum triglyceride levels were also important determinants of perioperative morbidity. In view of the increasing epidemic of obesity and the popularity of bariatric surgical procedures, we propose that additional clinical and metabolic research focusing on the understanding of the complex relationship among obesity, positive energy balance, weight gain, and perioperative

  15. Photoinduced optical anisotropy in azobenzene methacrylate block copolymers: Influence of molecular weight and irradiation conditions

    Gimeno, Sofia; Forcen, Patricia; Oriol, Luis

    2009-01-01

    The photoinduced anisotropy in a series of azomethacrylate block copolymers with different Molecular weights and azo contents has been investigated under several irradiation conditions. Depending on molecular weight and composition, different microstructures (disordered, lamellar, spherical) appe...

  16. Prophylaxis of postoperative thromboembolism with low molecular weight heparins

    Jørgensen, L N; Wille-Jørgensen, P; Hauch, O

    1993-01-01

    To evaluate the thromboprophylactic use of low molecular weight heparins (LMWHs), publications from 27 orthopaedic trials and 35 studies of patients undergoing general or gynaecological surgery were scrutinized and subjected to a partial meta-analysis. In orthopaedic surgery, LMWHs were superior...... to placebo or dextran and at least as efficient as unfractionated heparin in the prevention of deep vein thrombosis (DVT). Compared with unfractionated heparin, one of the LMWH preparations significantly reduced the total incidence of DVT. The rate of non-fatal pulmonary embolism was 0.49 per cent...

  17. Isotope chemistry and molecular structure. The WINIMAX weighting factor

    Lee, M.W.; Bigeleisen, J.

    1979-01-01

    The modulating coefficients for the finite polynomial expansion of the logarithm of the reduced partition function, lnb (u), of a harmonic oscillator have been obtained for the range of 0 6 . It is shown that this weighting function is near optimum to insure minimum amplitudes of oscillation in the expansion of lnb (u) as a function of the order of the expansion and to include most of the important molecular structure information contained in the moments of the eigenvalues. Beyond Σu/sub i/ 6 , there is little new structural information

  18. Molecular weight dependence of exciton diffusion in poly(3-hexylthiophene)

    Masri, Zarifi; Ruseckas, Arvydas; Emelianova, Evguenia V.

    2013-01-01

    A joint experimental and theoretical study of singlet exciton diffusion in spin-coated poly(3-hexylthiophene) (P3HT) films and its dependence on molecular weight is presented. The results show that exciton diffusion is fast along the co-facial π–π aggregates of polymer chromophores and about 100...... times slower in the lateral direction between aggregates. Exciton hopping between aggregates is found to show a subtle dependence on interchain coupling, aggregate size, and Boltzmann statistics. Additionally, a clear correlation is observed between the effective exciton diffusion coefficient...

  19. Hofmeister effect on thermo-responsive poly(propylene oxide): Role of polymer molecular weight and concentration

    Moghaddam, Saeed Zajforoushan; Thormann, Esben

    2016-01-01

    ) salts on aqueous solutions of poly(propylene oxide) (PPO) is studied. Four different molecular weights of PPO were investigated, to determine how the variation in the polymer coil size affects the Hofmeister effect. The investigation was further conducted for different PPO concentrations, in order...... with the transition. It was observed that increasing the molecular weight weakens the effect of the both salts, which is interpreted in terms of a scaling law between the molecular weight and the accessible surface area of the polymers. Increasing the PPO concentration further diminished the NaCl effect...

  20. Development of haplotype-specific molecular markers for the low-molecular-weight glutenin subunits

    Low-molecular-weight glutenin subunits (LMW-GSs) are one of the major components of gluten and their allelic variation has been widely associated with numerous wheat end-use quality parameters. These proteins are encoded by multigene families located at the orthologous Glu-3 loci (Glu-A3, Glu-B3 and...

  1. Influence of molecular weight on the fracture properties of aliphatic polyketone terpolymers

    Zuiderduin, W.C.J.; Homminga, D.S.; Homminga, D.S.; Huetink, Han; Gaymans, R.J.

    2003-01-01

    The influence of polymer molecular weight on the mechanical properties of aliphatic polyketones was investigated. The molecular weight varied from 100,000 to 300,000 g mol21. The crystallinity was found to be independent of polymer molecular weight, as was the glass transition temperature. The yield

  2. Increasing Incidence of Infants with Low Birth Weight in Oman

    Islam, M. Mazharul

    2015-01-01

    This review article provides an overview of the levels, trends and some possible explanations for the increasing rate of low birth weight (LBW) infants in Oman. LBW data from national health surveys in Oman, and published reports from Oman’s Ministry of Health and the World Health Organization were collected and assessed between January and August 2014. Oman’s LBW rate has been increasing since the 1980s. It was approximately 4% in 1980 and had nearly doubled (8.1%) by 2000. Since then, it has shown a slow but steady rise, reaching 10% in recent times. High rates of consanguinity, premature births, number of increased pregnancies at an older maternal age and changing lifestyles are some important factors related to the increasing rate of LBW in Oman. The underlying causes of this increase need to be understood and addressed in obstetric policies and practices in order to reduce the rate of LBW in Oman. PMID:26052449

  3. Increasing Incidence of Infants with Low Birth Weight in Oman

    M. Mazharul Islam

    2015-05-01

    Full Text Available This review article provides an overview of the levels, trends and some possible explanations for the increasing rate of low birth weight (LBW infants in Oman. LBW data from national health surveys in Oman, and published reports from Oman’s Ministry of Health and the World Health Organization were collected and assessed between January and August 2014. Oman’s LBW rate has been increasing since the 1980s. It was approximately 4% in 1980 and had nearly doubled (8.1% by 2000. Since then, it has shown a slow but steady rise, reaching 10% in recent times. High rates of consanguinity, premature births, number of increased pregnancies at an older maternal age and changing lifestyles are some important factors related to the increasing rate of LBW in Oman. The underlying causes of this increase need to be understood and addressed in obstetric policies and practices in order to reduce the rate of LBW in Oman.

  4. MALDI matrices for low molecular weight compounds: an endless story?

    Calvano, Cosima Damiana; Monopoli, Antonio; Cataldi, Tommaso R I; Palmisano, Francesco

    2018-04-23

    Since its introduction in the 1980s, matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) has gained a prominent role in the analysis of high molecular weight biomolecules such as proteins, peptides, oligonucleotides, and polysaccharides. Its application to low molecular weight compounds has remained for long time challenging due to the spectral interferences produced by conventional organic matrices in the low m/z window. To overcome this problem, specific sample preparation such as analyte/matrix derivatization, addition of dopants, or sophisticated deposition technique especially useful for imaging experiments, have been proposed. Alternative approaches based on second generation (rationally designed) organic matrices, ionic liquids, and inorganic matrices, including metallic nanoparticles, have been the object of intense and continuous research efforts. Definite evidences are now provided that MALDI MS represents a powerful and invaluable analytical tool also for small molecules, including their quantification, thus opening new, exciting applications in metabolomics and imaging mass spectrometry. This review is intended to offer a concise critical overview of the most recent achievements about MALDI matrices capable of specifically address the challenging issue of small molecules analysis. Graphical abstract An ideal Book of matrices for MALDI MS of small molecules.

  5. Sociocultural influences on strategies to lose weight, gain weight, and increase muscles among ten cultural groups.

    McCabe, Marita P; Busija, Lucy; Fuller-Tyszkiewicz, Matthew; Ricciardelli, Lina; Mellor, David; Mussap, Alexander

    2015-01-01

    This study determined how sociocultural messages to change one's body are perceived by adolescents from different cultural groups. In total, 4904 adolescents, including Australian, Chilean, Chinese, Indo-Fijian, Indigenous Fijian, Greek, Malaysian, Chinese Malaysian, Tongans in New Zealand, and Tongans in Tonga, were surveyed about messages from family, peers, and the media to lose weight, gain weight, and increase muscles. Groups were best differentiated by family pressure to gain weight. Girls were more likely to receive the messages from multiple sociocultural sources whereas boys were more likely to receive the messages from the family. Some participants in a cultural group indicated higher, and others lower, levels of these sociocultural messages. These findings highlight the differences in sociocultural messages across cultural groups, but also that adolescents receive contrasting messages within a cultural group. These results demonstrate the difficulty in representing a particular message as being characteristic of each cultural group. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Effect of the molecular weight of a neutral polysaccharide on soy protein gelation.

    Monteiro, Sónia R; Lopes-da-Silva, José A

    2017-12-01

    The effects of galactomannans with different molecular weights on the heat-induced gelation characteristics of soybean protein were investigated using dynamic small-strain rheometry, under conditions where the proteins carry a net negative charge (pH7). Microstructure of the resulting gels was investigated by confocal laser scanning microscopy. Phase-separated systems were obtained with different morphologies and degree of phase separation, depending on both biopolymer concentrations and polysaccharide molecular weight. In general, a gelling enhancing effect on soy proteins was verified, despite extensive phase-separation processes observed at the higher polysaccharide molecular weight. This effect was demonstrated by an increase of the gelation rate, a decrease in the temperature at the onset of gelation, and an increase of gel stiffness and elastic character, with the length of polysaccharide chains. Overall, the results obtained established that the judicious selection of the galactomannan molecular weight may be used to modify the structure and gelation properties of soy proteins, originating a diversity of rheological characteristics and microstructures that will impact on the design of novel food formulations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Radiodegradation process in PVDF with different molecular weight

    Silva, L.; Batista, A.S.M.; Nascimento, J.P.; Furtado, C.A.; Faria, L.O.

    2017-01-01

    Poly(vinylidene fluoride) (PVDF) is a semi-crystalline polymer with several industrial applications due to its mechanical, ferroelectric and biocompatibility properties. Due to the particularity of some of its applications this polymer is exposed to high energy radiation, for example in the aerospace industry and with biomaterial, in sterilization processes. In this sense it is of interest studies that evaluate the radiodegradation of this material, as a way to predict its mechanical behavior after processes of exposure to gamma radiation. In this study the radioresistance of PVDF with different molecular weights is evaluated, considering that large molecular chains can provide greater resistance than smaller chains. Method: PVDF samples with different molecular weights were produced by the solvent dilution process. They were irradiated with gamma doses of 100, 300, 500, 1000 and 2000 kGy with a source of cobalt in the Laboratório de Irradiação Gama (LIG) of the Centro de Desenvolvimento da Tecnologia Nuclear (CDTN). FTIR, UV-Vis, DSC and XRD analyzes were used to evaluate the induced radiodegradation processes immediately after irradiation and one month later. Results: The FTIR and UV-Vis analyzes showed formation of unsaturations in the polymer chains. The DSC technique showed a drop in the crystalline fraction of the polymer confirmed by the XRD technique. Conclusion: Post-irradiation sample evaluations are discussed in terms of the effect of high energy ionizing radiation on polymeric mate-rials for industrial and biomedical use for safety in quality assurance and performance in service. (author)

  8. Radiodegradation process in PVDF with different molecular weight

    Silva, L.; Batista, A.S.M., E-mail: adriananuclear@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil); Nascimento, J.P.; Furtado, C.A.; Faria, L.O. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2017-07-01

    Poly(vinylidene fluoride) (PVDF) is a semi-crystalline polymer with several industrial applications due to its mechanical, ferroelectric and biocompatibility properties. Due to the particularity of some of its applications this polymer is exposed to high energy radiation, for example in the aerospace industry and with biomaterial, in sterilization processes. In this sense it is of interest studies that evaluate the radiodegradation of this material, as a way to predict its mechanical behavior after processes of exposure to gamma radiation. In this study the radioresistance of PVDF with different molecular weights is evaluated, considering that large molecular chains can provide greater resistance than smaller chains. Method: PVDF samples with different molecular weights were produced by the solvent dilution process. They were irradiated with gamma doses of 100, 300, 500, 1000 and 2000 kGy with a source of cobalt in the Laboratório de Irradiação Gama (LIG) of the Centro de Desenvolvimento da Tecnologia Nuclear (CDTN). FTIR, UV-Vis, DSC and XRD analyzes were used to evaluate the induced radiodegradation processes immediately after irradiation and one month later. Results: The FTIR and UV-Vis analyzes showed formation of unsaturations in the polymer chains. The DSC technique showed a drop in the crystalline fraction of the polymer confirmed by the XRD technique. Conclusion: Post-irradiation sample evaluations are discussed in terms of the effect of high energy ionizing radiation on polymeric mate-rials for industrial and biomedical use for safety in quality assurance and performance in service. (author)

  9. Cellular Viscosity in Prokaryotes and Thermal Stability of Low Molecular Weight Biomolecules.

    Cuecas, Alba; Cruces, Jorge; Galisteo-López, Juan F; Peng, Xiaojun; Gonzalez, Juan M

    2016-08-23

    Some low molecular weight biomolecules, i.e., NAD(P)H, are unstable at high temperatures. The use of these biomolecules by thermophilic microorganisms has been scarcely analyzed. Herein, NADH stability has been studied at different temperatures and viscosities. NADH decay increased at increasing temperatures. At increasing viscosities, NADH decay rates decreased. Thus, maintaining relatively high cellular viscosity in cells could result in increased stability of low molecular weight biomolecules (i.e., NADH) at high temperatures, unlike what was previously deduced from studies in diluted water solutions. Cellular viscosity was determined using a fluorescent molecular rotor in various prokaryotes covering the range from 10 to 100°C. Some mesophiles showed the capability of changing cellular viscosity depending on growth temperature. Thermophiles and extreme thermophiles presented a relatively high cellular viscosity, suggesting this strategy as a reasonable mechanism to thrive under these high temperatures. Results substantiate the capability of thermophiles and extreme thermophiles (growth range 50-80°C) to stabilize and use generally considered unstable, universal low molecular weight biomolecules. In addition, this study represents a first report, to our knowledge, on cellular viscosity measurements in prokaryotes and it shows the dependency of prokaryotic cellular viscosity on species and growth temperature. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  10. Effects of molecular weight on the glass transition temperature in Durolon polycarbonate

    Miranda, Adelina; Sciani, Valdir

    1995-01-01

    The effect of variation of the dose rate on degradation mechanism of PC Durolon irradiated with gamma rays was determined trough out intrinsic viscosity and thermal analysis of DSC-type measurements. The results showed a linear relationship between the glass transition temperature and the viscosimetric average molecular weight. From the results it's shown that with an increased of the dose rate it also increases the degradation of the material. (author). 12 refs., 3 figs

  11. SYNTHESIS AND CHARACTERIZATION OF NEW STABILIZERS WITH OPTIMAL MOLECULAR WEIGHT

    Jiang-qing Pan

    2001-01-01

    Over 2 × l08 tons of polymers are produced every year, and a large portion of polymers faces the degradation problem. There are many effective methods to protect polymers against degradation and the addition of stabilizers to polymer remains the most convenient and effective way of enhancing polymer life and performance. In this article, a series of effective stabilizers with optimal molecular weight (MW), including common, monomeric and polymeric stabilizers (antioxidant and light stabilizer) were synthesized using isocyanation, controlled isocyanation, hydrosilylation, epoxide addition, macroreaction of stabilizing functional compounds and polymerization of monomeric stabilizers. The sructure and performance of these new stabilizers were characterized by using IR, NMR, MS, UV-spectra, XPS and elemental analysis. The current development of stabilizer synthesis was also reviewed.``

  12. Recent developments in separation of low molecular weight heparin anticoagulants.

    Sadowski, Radosław; Gadzała-Kopciuch, Renata; Buszewski, Bogusław

    2017-10-05

    The general function of anticoagulants is to prevent blood clotting and growing of the existing clots in blood vessels. In recent years, there has been a significant improvement in developing methods of prevention as well as pharmacologic and surgical treatment of thrombosis. For over the last two decades, low molecular weight heparins (LMWHs) have found their application in the antithrombotic diseases treatment. These types of drugs are widely used in clinical therapy. Despite the biological and medical importance of LMWHs, they have not been completely characterized in terms of their chemical structure. Due to both, the structural complexity of these anticoagulants and the presence of impurities, their structural characterization requires the employment of advanced analytical techniques. Since separation techniques play the key role in these endeavors, this review will focus on the presentation of recent developments in the separation of LMWH anticoagulants. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  13. Low-molecular-weight carbohydrates from red seaweeds

    Duarte, M.E.R.; Tischer, C.A.; Gorin, P.A.J.; Noseda, M.D.

    1997-01-01

    Red algae (Rhodophyta) produce, as their principal photosynthetic metabolites, low-molecular-weight carbohydrates and polyols. The former are heterosides consisting of galactose and glycerol and are produced by all the orders of Phodophyta except the ceramiales. They are named: floridoside [α-D-galactopyranosyl (1->2)-glycerol], isofloridoside D-form [α-D-galactopyranosyl-(1->)D-glycerol] and L-form [α-D-galactopyranosyl-(1->1)-L-glycerol] (Meng et al., 1987, Karsten et al., 1993). The Ceramiales synthesize the chemically related digeneaside [α-D-mannopyranosyl-(1->2)-L-glycerate] (Kirst, 1980). Some of the red seaweeds also produce polyols such as dulcitol and D-sorbitol (Karsten et al., 1992). (author)

  14. Low-molecular-weight carbohydrates from red seaweeds

    Duarte, M.E.R.; Tischer, C.A.; Gorin, P.A.J.; Noseda, M.D. [Parana Univ., Curitiba, PR (Brazil). Dept. de Bioquimica

    1997-12-31

    Red algae (Rhodophyta) produce, as their principal photosynthetic metabolites, low-molecular-weight carbohydrates and polyols. The former are heterosides consisting of galactose and glycerol and are produced by all the orders of Phodophyta except the ceramiales. They are named: floridoside [{alpha}-D-galactopyranosyl (1->2)-glycerol], isofloridoside D-form [{alpha}-D-galactopyranosyl-(1->)D-glycerol] and L-form [{alpha}-D-galactopyranosyl-(1->1)-L-glycerol] (Meng et al., 1987, Karsten et al., 1993). The Ceramiales synthesize the chemically related digeneaside [{alpha}-D-mannopyranosyl-(1->2)-L-glycerate] (Kirst, 1980). Some of the red seaweeds also produce polyols such as dulcitol and D-sorbitol (Karsten et al., 1992). (author) 4 refs., 8 figs., 1 tabs.

  15. Obstetric outcome with low molecular weight heparin therapy during pregnancy.

    Donnelly, J

    2012-01-01

    This was a prospective study of women attending a combined haematology\\/obstetric antenatal clinic in the National Maternity Hospital (2002-2008). Obstetric outcome in mothers treated with low molecular weight heparin (LMWH) was compared to the general obstetric population of 2006. There were 133 pregnancies in 105 women. 85 (63.9%) received prophylactic LMWH and 38 (28.6%) received therapeutic LMWH in pregnancy. 10 (7.5%) received postpartum prophylaxis only. The perinatal mortality rate was 7.6\\/1000 births. 14 (11.3%) women delivered preterm which is significantly higher than the hospital population rate (5.7%, p<0.05). Despite significantly higher labour induction rates (50% vs 29.2% p<0.01), there was no difference in CS rates compared to the general hospital population (15.4% vs 18.9%, NS). If carefully managed, these high-risk women can achieve similar vaginal delivery rates as the general obstetric population.

  16. [Correlation of molecular weight and nanofiltration mass transfer coefficient of phenolic acid composition from Salvia miltiorrhiza].

    Li, Cun-Yu; Wu, Xin; Gu, Jia-Mei; Li, Hong-Yang; Peng, Guo-Ping

    2018-04-01

    Based on the molecular sieving and solution-diffusion effect in nanofiltration separation, the correlation between initial concentration and mass transfer coefficient of three typical phenolic acids from Salvia miltiorrhiza was fitted to analyze the relationship among mass transfer coefficient, molecular weight and concentration. The experiment showed a linear relationship between operation pressure and membrane flux. Meanwhile, the membrane flux was gradually decayed with the increase of solute concentration. On the basis of the molecular sieving and solution-diffusion effect, the mass transfer coefficient and initial concentration of three phenolic acids showed a power function relationship, and the regression coefficients were all greater than 0.9. The mass transfer coefficient and molecular weight of three phenolic acids were negatively correlated with each other, and the order from high to low is protocatechualdehyde >rosmarinic acid> salvianolic acid B. The separation mechanism of nanofiltration for phenolic acids was further clarified through the analysis of the correlation of molecular weight and nanofiltration mass transfer coefficient. The findings provide references for nanofiltration separation, especially for traditional Chinese medicine with phenolic acids. Copyright© by the Chinese Pharmaceutical Association.

  17. Effect of electron beam radiation on the structure and mechanical properties of ultra high molecular weight polyethylene fibers

    Li Shujun; Sun Weijun; Liu Xiuju; Gao Yongzhong; Li Huisheng

    1998-01-01

    Ultra high molecular weight polyethylene fibers have been crosslinked by electron beam. The structure and mechanical properties of them have been investigated in different irradiation atmospheres. The obtained results show that the gel content and crosslinking density increase with the increase of dose, the swelling ratio and average molecular weight of crosslinked net decrease with the increase of dose, the tensile strength and failure elongation decrease with the increase of dose, the tensile modulus increases with the increase of dose. When the samples are irradiated in air, vacuum and acetylene atmospheres, the effect of irradiation in acetylene atmosphere is best

  18. The measurement of the molecular weight of humic acid by ultracentrifugation

    Gardner, M.P.

    1989-07-01

    This report is concerned with the application of ultracentrifuge methods to the determination of humic acid molecular weights. The work has been undertaken as part of the Co-Co club intercomparison exercise on humic acid characterisation. Knowledge of the molecular weight distribution of humic acid will be an important parameter in assessing the likely physical and chemical behaviour under the near-field environment. Molecular weights of a sample of purified Aldrich humic acid have been obtained by sedimentation velocity and sedimentation equilibrium studies using an analytical ultracentrifuge. The results have shown the material to be polydisperse with a weight average molecular weight in the region 2700 to 4000. (author)

  19. Low Molecular Weight Norbornadiene Derivatives for Molecular Solar-Thermal Energy Storage.

    Quant, Maria; Lennartson, Anders; Dreos, Ambra; Kuisma, Mikael; Erhart, Paul; Börjesson, Karl; Moth-Poulsen, Kasper

    2016-09-05

    Molecular solar-thermal energy storage systems are based on molecular switches that reversibly convert solar energy into chemical energy. Herein, we report the synthesis, characterization, and computational evaluation of a series of low molecular weight (193-260 g mol(-1) ) norbornadiene-quadricyclane systems. The molecules feature cyano acceptor and ethynyl-substituted aromatic donor groups, leading to a good match with solar irradiation, quantitative photo-thermal conversion between the norbornadiene and quadricyclane, as well as high energy storage densities (396-629 kJ kg(-1) ). The spectroscopic properties and energy storage capability have been further evaluated through density functional theory calculations, which indicate that the ethynyl moiety plays a critical role in obtaining the high oscillator strengths seen for these molecules. © 2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  20. Phosphorus release from phosphate rock and iron phosphate by low-molecular-weight organic acids.

    Xu, Ren-kou; Zhu, Yong-guan; Chittleborough, David

    2004-01-01

    Low-molecular-weight(LMW) organic acids widely exist in soils, particularly in the rhizosphere. A series of batch experiments were carried out to investigate the phosphorus release from rock phosphate and iron phosphate by low-molecular-weight organic acids. Results showed that citric acid had the highest capacity to solubilize P from both rock and iron phosphate. P solubilization from rock phosphate and iron phosphate resulted in net proton consumption. P release from rock phosphate was positively correlated with the pKa values. P release from iron phosphate was positively correlated with Fe-organic acid stability constants except for aromatic acids, but was notcorrelated with pKa. Increase in the concentrations of organic acids enhanced P solubilization from both rock and iron phosphate almost linearly. Addition of phenolic compounds further increased the P release from iron phosphate. Initial solution pH had much more substantial effect on P release from rock phosphate than from iron phosphate.

  1. Urinary high molecular weight matrix metalloproteinases as non-invasive biomarker for detection of bladder cancer

    Mohammed, Mohammed A; Seleim, Manar F; Abdalla, Mohga S; Sharada, Hayat M; Abdel Wahab, Abdel Hady A

    2013-01-01

    Background Matrix Metalloproteinases (MMPs) are key molecules for tumor growth, invasion and metastasis. Over-expression of different MMPs in tumor tissues can disturb the homeostasis and increase the level of various body fluids. Many MMPs including high molecular weights (HMWs) were detected in the urine of prostate and bladder cancer patients. Our aim here is to assess the usefulness of HMW MMPs as non invasive biomarkers in bilharzial bladder cancer in Egyptian patients. Methods The activ...

  2. Effect of the different chain transfer agents on molecular weight and optical properties of poly(methyl methacrylate)

    Çetinkaya, Onur; Demirci, Gökhan; Mergo, Paweł

    2017-08-01

    Investigation of molecular weight and optical properties of poly(methyl metacrylate) (PMMA) polymerized in house with different chain transfer agents was studied. Isopropyl alcohol (IPA), n-butyl mercaptan (nBMC) and pentamethyl disilane (PMDS) were used as chain transfer agents. The molecular weight (Mw) of PMMA samples were measured by Ostwald viscometer. Mw of bulk polymer samples were decreased with increase the concentration of chain transfer agents (CTA). Since reactivity of used CTAs is not same, molecular weights of samples which were produced with different type of CTA but same concentration of CTA was varied. Higher concentration of n-BMC showed higher scattering. Transmission of samples could not be correlated with different concentration of CTA. Refractive index of samples was not affected by concentration of CTA nevertheless higher molecular weight of CTA showed higher refractive index.

  3. Low molecular-weight phenols in Tannat wines made by alternative winemaking procedures.

    Favre, Guzmán; Peña-Neira, Álvaro; Baldi, Cecilia; Hernández, Natalia; Traverso, Sofía; Gil, Graciela; González-Neves, Gustavo

    2014-09-01

    Low molecular weight phenols of Tannat red wines produced by Traditional Maceration (TM), Prefermentative Cold Maceration (PCM), Maceration Enzyme (ENZ) and grape-Seed Tannins additions (ST), were performed and discussed. Alternatives to TM increased wine phenolic contents but unequally, ST increased mainly smaller flavans-3-ol, PCM anthocyanins and ENZ proanthocyanidins (up to 2250 mg/L). However low molecular weight flavan-3-ols remained below 9 mg/L in all wines, showing that there is not necessarily a correspondence between wine richness in total tannins and flavan-3-ols contents at low molecular weight. PCM wines had particularly high concentrations of tyrosol and tryptophol, yeast metabolism derived compounds. The use of grape-seed enological tannins did not increase grape seed derived phenolic compounds such as gallic acid. Caftaric acid was found in concentrations much higher than those reported in other grape varieties. Wine phenolic content and composition was considerably affected by the winemaking procedures tested. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Role of Molecular Weight on the Mechanical Device Properties of Organic Polymer Solar Cells

    Bruner, Christopher

    2014-02-11

    For semiconducting polymers, such as regioregular poly(3-hexylthiophene-2, 5-diyl) (rr-P3HT), the molecular weight has been correlated to charge carrier field-effect mobilities, surface morphology, and gelation rates in solution and therefore has important implications for long-Term reliability, manufacturing, and future applications of electronic organic thin films. In this work, we show that the molecular weight rr-P3HT in organic solar cells can also significantly change the internal cohesion of the photoactive layer using micromechanical testing techniques. Cohesive values ranged from ∼0.5 to ∼17 J m -2, following the general trend of greater cohesion with increasing molecular weight. Using nanodynamic mechanical analysis, we attribute the increase in cohesion to increased plasticity which helps dissipate the applied energy. Finally, we correlate photovoltaic efficiency with cohesion to assess the device physics pertinent to optimizing device reliability. This research elucidates the fundamental parameters which affect both the mechanical stability and efficiency of polymer solar cells. © 2014 American Chemical Society.

  5. Glomerular sieving of high molecular weight proteins in proteinuric rats

    Bertolatus, J.A.; Abuyousef, M.; Hunsicker, L.G.

    1987-01-01

    To characterize the permeability of the glomerular capillary wall to high molecular weight proteins in normal and proteinuric rats, we determined the glomerular sieving coefficients (GSC) of radioiodinated marker proteins of known size and charge by means of a paired label, tissue accumulation method previously validated in this laboratory. In one group of rats (Series A) the GSCs of 125 I-anionic IgG (aIgG-molecular weight [mol wt] 150,000, pI 4.9) and 131 I-neutral IgG (nIgG-pI 7.4 to 7.6) were measured simultaneously. In Series B, the GSC of a second anionic marker, 131 I-human ceruloplasmin (Crp-mol wt 137,000, pI 4.9) was compared to that of 125 I-nIgG. As in the previous report, the labeled proteins were not degraded or deiodinated during the 20 minute clearance period for GSC determination. Within Series A and B, three subgroups of rats were studied: control saline-infused rats, rats made acutely proteinuric by infusion of the polycation hexadimethrine (HDM), and rats with chronic doxorubicin (Adriamycin-Adria) nephrosis. In the control rats, GSCs for the anionic markers aIgG (Series A) or Crp (Series B) were significantly greater than that of nIgG (both series). These large proteins crossed the filtration barrier by a different pathway from that available to smaller neutral molecules the size of albumin, which in our previous study had a much higher GSC than a native, anionic albumin marker. In a third group of control rats only (Series C), the GSCs of native anionic bovine albumin (BSA) and nIgG were compared directly. The GSC of BSA (0.0029) was only slightly larger than the GSC of nIgG (0.0025), indicating that most of the native albumin crosses the glomerular capillary wall via a nonselective pathway similar to that available to nIgG. The results in the control groups are compatible with recently-described heteroporous models of glomerular size selectivity

  6. Effect of thermal treatment on potato starch evidenced by EPR, XRD and molecular weight distribution.

    Bidzińska, Ewa; Michalec, Marek; Pawcenis, Dominika

    2015-12-01

    Effect of heating of the potato starch on damages of its structure was investigated by quantitative electron paramagnetic resonance (EPR) spectroscopy, X-ray diffraction and determination of the molecular weight distribution. The measurements were performed in the temperature range commonly used for starch modifications optimizing properties important for industrial applications. Upon thermal treatment, because of breaking of the polymer chains, diminishing of the average molecular weights occurred, which significantly influences generation of radicals, evidenced by EPR. For the relatively mild conditions, with heating parameters not exceeding temperature 230 °C and time of heating equal to 30 min a moderate changes of both the number of thermally generated radicals and the mean molecular weight of the starch were observed. After more drastic thermal treatment (e.g. 2 h at 230 °C), a rapid increase in the radical amount occurred, which was accompanied by significant reduction of the starch molecular size and crystallinity. Experimentally established threshold values of heating parameters should not be exceeded in order to avoid excessive damages of the starch structure accompanied by the formation of the redundant amount of radicals. This requirement is important for industrial applications, because significant destruction of the starch matrix might annihilate the positive influence of the previously performed intentional starch modification. Copyright © 2015 John Wiley & Sons, Ltd.

  7. Molecular imprinted polymer-coated optical fiber sensor for the identification of low molecular weight molecules.

    Lépinay, Sandrine; Ianoul, Anatoli; Albert, Jacques

    2014-10-01

    A biomimetic optical probe for detecting low molecular weight molecules (maltol, 3-hydroxy-2-methyl-4H-pyran-4-one, molecular weight of 126.11 g/mol), was designed, fabricated, and characterized. The sensor couples a molecular imprinted polymer (MIP) and the Bragg grating refractometry technology into an optical fiber. The probe is fabricated first by inscribing tilted grating planes in the core of the fiber, and then by photopolymerization to immobilize a maltol imprinted MIP on the fiber cladding surface over the Bragg grating. The sensor response to the presence of maltol in different media is obtained by spectral interrogation of the fiber transmission signal. The results showed that the limit of detection of the sensor reached 1 ng/mL in pure water with a sensitivity of 6.3 × 10(8)pm/M. The selectivity of the sensor against other compounds and its reusability were also studied experimentally. Finally, the unambiguous detection of concentrations as little as 10nM of maltol in complex media (real food samples) by the MIP-coated tilted fiber Bragg grating sensor was demonstrated. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Intravitreal low molecular weight heparin in PVR surgery.

    Kumar Atul

    2003-01-01

    Full Text Available Purpose: To evaluate the efficacy of low molecular weight heparin (LMWH in prevention of postoperative fibrin formation following vitreoretinal surgery with proliferative vitreoretinopathy (PVR. Material and Methods: Thirty consecutive patients of retinal detachment with advanced PVR were enrolled in the study. They were randomised to study and control groups (n = 15 each. Study group patients received vitreoretinal surgery with 5 IU/cc of LMWH in vitrectomy infusion fluid. The control group patients received vitroretinal surgery without heparin in the infusion fluid. Patients were followed up at 1 week, 1 month and 3 months after surgery. Postoperative bleeding, media clarity, best-corrected visual acuity and success of the surgery at the end of 3 months were compared between the two groups. Results: At each follow-up visit, the study group showed a better media clarity, which was statistically significant ( P = 0.0042. The study group had a 50% better chance of retinal reattachment compared to the control group. Five patients had intraoperative bleeding in the study group (33% compared to 3 patients in the control group (20%. Conclusion: Use of intravitreal LMWH prevents postoperative fibrin formation and is beneficial in repair of retinal detachments with PVR.

  9. Disassembled DJ-1 high molecular weight complex in cortex mitochondria from Parkinson's disease patients

    Adler Charles

    2009-07-01

    Full Text Available Abstract Correction to Nural H, He P, Beach T, Sue L, Xia W, Shen Y. Disassembled DJ-1 high molecular weight complex in cortex mitochondria from Parkinson's disease patients Molecular Neurodegeneration 2009, 4:23.

  10. Relationship of molecular weight distribution profile of unreduced gluten protein extracts with quality characteristics of bread.

    Chaudhary, Nisha; Dangi, Priya; Khatkar, B S

    2016-11-01

    A statistical correlation was established among the molecular weight distribution patterns of unreduced gluten proteins and physicochemical, rheological and bread-making quality characteristics of wheat varieties. Size exclusion chromatography fractionated the gluten proteins apparently into five peaks. Peak I signified glutenins (30-130kDa), peak II as gliadins (20-55kDa), peak III as very low molecular weight monomeric gliadins (10-28kDa), peak IV and V, collectively, as albumins and globulins (bread loaf volume (r=0.848(∗∗)); however, peak II had negative (r=-0.818(∗∗)) impact. Bread firmness increased with increment in peak II (r=0.625(∗∗)), and decreased with accretion in peak I (r=-0.623(∗∗)). Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Electrospinning and characterization of polyamide 66 nanofibers with different molecular weights

    Lilia Muller Guerrini

    2009-06-01

    Full Text Available Polyamide 66 (PA66 nanofibers of different molecular weights were obtained by electrospinning of formic acid solutions. An ionic salt, NaCl, was also added to the solutions to increase the conductivity. PA66 concentrations between 15-17 wt.(%/v and electrical fields between 2.0 and 2.5 kV/cm were the best conditions to produce the smallest nanofibers; however, the addition of NaCl increased the fibers average diameters.The characterization of the fibers was done by scanning electron microscopy (SEM, differential scanning calorimetry (DSC, wide angle X rays diffraction (WAXD and Fourier Transformed Infrared (FTIR. As the molecular weight decreased, the nanofibers average diameters also decreased; however, critical number average and weight average molecular weights were necessary for electrospinning. As the amounts of carboxyl terminal groups (CTG increased, the nanofibers average diameters decreased; however, above CTG's critical values of 8.7 x 10-5 mol.g-1 no electrospinning was possible. The addition of ionic salt increased the electrical conductivity of the solutions and increased the nanofibers' average diameters. By DSC, residual solvent in all the electrospun mats was found; two melting endotherms, one between 248 and 258 °C and the other one between 258 and 267 °C, depending on the sample were also observed. These endotherms were attributed to the melting, re-crystallization and re-melting of the PA66 α-phase. The nanofibers had low % of crystallinity compared to a textile fiber. By WAXS and FTIR, confirmation of the presence of α-phase crystals, of small dimensions and highly imperfect and of a very small amount of β and γ-phases crystals in the nanofibers structure was obtained.

  12. Micellization of symmetric PEP-PEO block copolymers in water molecular weight dependence

    Kaya, H; Allgaier, J; Stellbrink, J; Richter, D

    2002-01-01

    The micellar behaviour of the amphiphilic block copolymer poly-(ethylene-propylene)-poly-(ethylene oxide) (PEP-PEO) in aqueous solution has been studied with small-angle neutron scattering. The polymer was studied over a wide range of molecular weights, always keeping the volume of the blocks equal. The scattering behaviour of the solutions showed that a morphological transition takes place upon lowering the molecular weight. The high molecular weight block copolymers all build spherical, monodisperse micelles with large aggregation numbers. At low molecular weights, however, cylindrical micelles are formed. An interesting intermediate case is represented by the PEP2-PEO2 system, in which a morphological transition occurs upon dilution. (orig.)

  13. Effect of molecular weight reduction by gamma irradiation on chitosan film properties

    García, Mario A., E-mail: marioifal@gmail.com [Pharmacy and Food Institute, University of Havana, St. 222 No. 2317, ZC 13600 Havana (Cuba); Pérez, Liliam [Pharmacy and Food Institute, University of Havana, St. 222 No. 2317, ZC 13600 Havana (Cuba); Paz, Nilia de la [Drugs Research and Development Center, Ave. 26 No. 1605, Havana (Cuba); González, Juan [Food Industry Research Institute, Carretera al Guatao km 3 1/2, Havana, CP 19200 (Cuba); Rapado, Manuel [Radiobiology Department, Center for Technological Applications and Nuclear Development, St. 30 No. 502, Playa, Havana (Cuba); Casariego, Alicia [Pharmacy and Food Institute, University of Havana, St. 222 No. 2317, ZC 13600 Havana (Cuba)

    2015-10-01

    The present work aimed the influence of molecular weight (MW) reduction by irradiation with {sup 60}Co and polymer concentration on some physical properties of chitosan films. Irradiation of chitosan with a MW of 275.221 kDa and 74.74% of deacetylation degree was performed using a {sup 60}Co source to provide doses of 5, 10, 20 and 50 kGy to obtain chitosans with molecular weights of 247.847, 221.563, 126.469 and 77.063 kDa, respectively. Films were prepared via the solution casting method. Film-forming solutions (FFS) of chitosan irradiated or not, were prepared at 1.5 and 2% (w/v) in a solution of lactic acid at 1% (v/v) and 0.1% (v/v) of Tween 80. The FFS were poured into glass plates of 400 cm{sup 2} and dried at 60 °C during 10 h without airflow. The decrease of MW and increase of chitosan concentration increased the tensil strength and water vapor permeability while decreased the elongation at break of the films. The chitosan MW did not significantly influence (p > 0.05) the water solubility of films within a same polymer concentration. There was a decrease in the films' brightness with the increase of concentration and a decrease of the MW of irradiated chitosan, while the b* values of films increased and there was an increasing tendency of their apparent opacity. - Highlights: • MW reduction by {sup 60}Co irradiation increased the tensil strength of chitosan films. • MW reduction increased the water vapor permeability of chitosan films. • MW did not affect the films' water solubility within a same chitosan concentration. • Films' brightness decreased with the chitosan molecular weight reduction.

  14. Effect of molecular weight reduction by gamma irradiation on chitosan film properties

    García, Mario A.; Pérez, Liliam; Paz, Nilia de la; González, Juan; Rapado, Manuel; Casariego, Alicia

    2015-01-01

    The present work aimed the influence of molecular weight (MW) reduction by irradiation with 60 Co and polymer concentration on some physical properties of chitosan films. Irradiation of chitosan with a MW of 275.221 kDa and 74.74% of deacetylation degree was performed using a 60 Co source to provide doses of 5, 10, 20 and 50 kGy to obtain chitosans with molecular weights of 247.847, 221.563, 126.469 and 77.063 kDa, respectively. Films were prepared via the solution casting method. Film-forming solutions (FFS) of chitosan irradiated or not, were prepared at 1.5 and 2% (w/v) in a solution of lactic acid at 1% (v/v) and 0.1% (v/v) of Tween 80. The FFS were poured into glass plates of 400 cm 2 and dried at 60 °C during 10 h without airflow. The decrease of MW and increase of chitosan concentration increased the tensil strength and water vapor permeability while decreased the elongation at break of the films. The chitosan MW did not significantly influence (p > 0.05) the water solubility of films within a same polymer concentration. There was a decrease in the films' brightness with the increase of concentration and a decrease of the MW of irradiated chitosan, while the b* values of films increased and there was an increasing tendency of their apparent opacity. - Highlights: • MW reduction by 60 Co irradiation increased the tensil strength of chitosan films. • MW reduction increased the water vapor permeability of chitosan films. • MW did not affect the films' water solubility within a same chitosan concentration. • Films' brightness decreased with the chitosan molecular weight reduction

  15. Respiratory clearance of aerosolized radioactive solutes of varying molecular weight

    Huchon, G.J.; Montgomery, A.B.; Lipavsky, A.; Hoeffel, J.M.; Murray, J.F.

    1987-01-01

    To determine the influence of varying molecular weight (mol wt) on respiratory clearance of aerosolized solutes, we studied eight radiopharmaceuticals, each administered to four dogs: sodium /sup 99m/Tc pertechnetate (TcO4), /sup 99m/Tc glucoheptonate ([/sup 99m/Tc]GH), 51Cr-ethylenedinitrotetraacetate ([51Cr]EDTA), /sup 99m/Tc diethylenetriaminepentaacetate ([99mTc] DTPA), 111 In diethylenetriaminepentaacetate ([ 111 In]DTPA), 67 Ga desferoxaminemesylate ([ 67 Ga]DFOM), /sup 99m/Tc dextran ([/sup 99m/Tc]DX) and 111 In transferrin ([ 111 In]TF). After aerosolization (0.8 m MMD, 2.4 GSD), clearance was determined for 30 min and then corrected by intravenous injection for nonairspace radioactivity. In-TF clearance (0.11 +/- 0.10%/min) was lower than TcO4 (6.32 +/- 0.62%/min), [/sup 99m/Tc]GH (1.50 +/- 0.37%/min), [ 51 Cr]EDTA (2.38 +/- 1.02%/min), [/sup 99m/Tc]DTPA (3.51 +/- 0.40%/min), [ 111 In]DTPA (2.35 +/- 0.42%/min), [ 67 Ga] DFOM (1.99 +/- 0.49%/min) and [/sup 99m/Tc]DX (1.81 +/- 0.75%/min) clearances (p less than 0.001). TcO4 clearance was higher than others (p less than 0.001). Technetium binding to DX was unsatisfactory; aerosolization caused unbinding from DTPA. We conclude that respiratory clearance of large mol wt solutes within 30 min is negligible and, that clearance of molecules between 347-5099 daltons differs greatly, suggesting that binding and/or intrapulmonary retention affect transfer

  16. Properties of crosslinked ultra-high-molecular-weight polyethylene.

    Lewis, G

    2001-02-01

    Substantially reducing the rate of generation of wear particles at the surfaces of ultra-high-molecular-weight polyethylene (UHMWPE) orthopedic implant bearing components, in vivo, is widely regarded as one of the most formidable challenges in modern arthroplasty. In the light of this, much research attention has been paid to the myriad of endogenous and exogenous factors that have been postulated to affect this wear rate, one such factor being the polymer itself. In recent years, there has been a resurgence of interest in crosslinking the polymer as a way of improving its properties that are considered relevant to its use for fabricating bearing components. Such properties include wear resistance, fatigue life, and fatigue crack propagation rate. Although a large volume of literature exists on the topic on the impact of crosslinking on the properties of UHMWPE, no critical appraisal of this literature has been published. This is one of the goals of the present article, which emphasizes three aspects. The first is the trade-off between improvement in wear resistance and depreciation in other mechanical and physical properties. The second aspect is the presentation of a method of estimating the optimal value of a crosslinking process variable (such as dose in radiation-induced crosslinking) that takes into account this trade-off. The third aspect is the description of a collection of under- and unexplored research areas in the field of crosslinked UHMWPE, such as the role of starting resin on the properties of the crosslinked polymer, and the in vitro evaluation of the wear rate of crosslinked tibial inserts and other bearing components that, in vivo, are subjected to nearly unidirectional motion.

  17. High Molecular Weight Isoforms of Growth Hormone In Cells of the Immune System

    Weigent, Douglas A.

    2013-01-01

    A substantial body of research exists to support the idea that cells of the immune system produce growth hormone (GH). However, the structure and mechanism of action of lymphocyte-derived GH continues to remain largely unknown. Here we present the results of Western analysis of whole cell extracts showing that different molecular weight isoforms of GH of approximately 100 kDa, 65 kDa, and 48 kDa can be detected in primary mouse cells of the immune system and in the mouse EL4 cell line. The identity of the 65 kDa and 48 kDa isoforms of GH were confirmed by mass spectrometry. The various isoforms were detected in both enriched T and B spleen cell populations. The large molecular weight isoform appears to reside primarily in the cytoplasm whereas the lower molecular weight 65 kDa and 48 kDa isoforms were detected primarily in the nucleus. These results also suggest that GH isoforms are induced by oxidative stress. In EL4 cells overexpressing GH, the expression of luciferase controlled by a promoter containing the antioxidant response element is increased almost three-fold above control. The data suggest that the induction of isoforms of the GH molecule in cells of the immune system may be an important mechanism of adaptation and/or protection of lymphoid cells under conditions of oxidative stress. PMID:21741628

  18. Structural modifications of ultra-high molecular weight polyethylene (UHMWPE) processed in attritor type mill

    Gabriel, Melina C.; Carvalho, Benjamim de M.; Pinheiro, Luis A.; Cintho, Osvaldo M.; Capocchi, Jose D.T.; Kubaski, Evaldo T.

    2009-01-01

    Ultra-high molecular weight polyethylene (UHMWPE) is a polyethylene that has a high melt viscosity, hence its processing becomes very difficult. High-energy mechanical milling provides physical and chemical changes in polymers that have been studied recently. In order to study these changes in UHMWPE, powder of this polymer was mechanical milled in attritor type mill with a ball-to-powder weight ratio of 40:1 for 8 hours, varying the rotation speed: 200, 300, 400, 500 e 600 rpm. The polymer was characterized by scanning electron microscopy (SEM) and xray diffraction (XRD). From the XRD results it was noted that as the rotation speed increased the monoclinic phase also increased up to 500 rpm. For 600 rpm, the amount of monoclinic phase apparently decreased. At this rotation speed, the deformation rate probably increased the process temperature, allowing the monoclinic phase to return to its initial structural orthorhombic form. (author)

  19. Effect of Molecular Weight on the Thermal and Spectroscopic Properties of Poly(vinyl alcohol) Films

    Khafagy, R.M.; Abd El-Kader, K.M.; Badr, Y.A.

    2009-01-01

    Thin films of Poly(vinyl alcohol) (PVA) with molecular weights 5000, 17000,72000 and 125000 g/mol were prepared by casting technique.Samples were thermally and spectroscopically investigated using TGA, DSC, FTIR and FT-Raman spectroscopy, in order to show how the thermal stability and structure of PVA might be correlated with its molecular weight. Thermal analysis showed that samples degrade in two steps mechanism. The mechanism observed for degradation in an inert atmosphere was in accordance with the accepted mechanism of elimination followed by pyrolisation. PVA 5000MW and PVA 17000Mw showed almost similar thermal behavior due to their expected similar structure. PVA 72000Mw showed lower thermal stability since it is characterized with the presence of the unstable C-O-C ether linkages, which lead to the fast melting of this sample. PVA 125000Mw showed the highest thermal stability because crosslinking of the main chains takes place due to introducing additional PVA units, which substitute each over oxygen atom. ΔH values obtained from DSC showed good accordance with TGA and Drtg analysis. Moreover, FTIR and FT-Raman results agreed well with thermal analysis, and confirmed our supposed structural changes which might take place as the molecular weight of the sample changes: since the water uptake, presence of ether linkages, and double bonds formulation due to crosslinking, were confirmed with FTIR and FT-Raman spectral analysis. The crystallinity percentage of the samples was calculated from Raman spectra and results confirmed our spectroscopic explanations. The thermal and spectroscopic behavior of the samples was explained as a result of the competitive action of at least three factors due to increasing the molecular weight: (i) diminution of the existing physical network due to changes in hydrogen bonding; (ii) formation of a chemical network; and (iii) introduction of flexible moieties due to the specific chemical structure after crosslinking

  20. Effect of alkali lignins with different molecular weights from alkali pretreated rice straw hydrolyzate on enzymatic hydrolysis.

    Li, Yun; Qi, Benkun; Luo, Jianquan; Wan, Yinhua

    2016-01-01

    This study investigated the effect of alkali lignins with different molecular weights on enzymatic hydrolysis of lignocellulose. Different alkali lignins fractions, which were obtained from cascade ultrafiltration, were added into the dilute acid pretreated (DAP) and alkali pretreated (AP) rice straws respectively during enzymatic hydrolysis. The results showed that the addition of alkali lignins enhanced the hydrolysis and the enhancement for hydrolysis increased with increasing molecular weights of alkali lignins, with maximum enhancement being 28.69% for DAP and 20.05% for AP, respectively. The enhancement was partly attributed to the improved cellulase activity, and filter paper activity increased by 18.03% when adding lignin with highest molecular weight. It was found that the enhancement of enzymatic hydrolysis was correlated with the adsorption affinity of cellulase on alkali lignins, and the difference in surface charge and hydrophobicity of alkali lignins were responsible for the difference in affinity between cellulase and lignins. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. In vitro studies of PEG thin films with different molecular weights deposited by MAPLE

    Paun, Irina Alexandra; Ion, Valentin; Luculescu, Catalin-Romeo

    2012-01-01

    and their behavior in vitro. Thus, immersion in PBS induced swelling of the PEG films, which was more pronounced for PEG polymers of higher molecular weight. Prior to immersion in PBS, the PEG films of higher molecular weight were more hydrophilic, the water contact angles decreasing from ∼66 grd for PEG400 to ∼41...

  2. Low molecular weight heparin versus unfractionated heparin in the initial treatment of venous thromboembolism

    Hettiarachchi, R. J.; Prins, M. H.; Lensing, A. W.; Buller, H. R.

    1998-01-01

    In this review, we analyze data from randomized trials in which low molecular weight heparin was compared with unfractionated heparin, both to estimate the treatment effect of low molecular weight heparin in the initial treatment of venous thromboembolism and to evaluate the effect of the varied

  3. Hyaluronic acid-coated chitosan nanoparticles: molecular weight-dependent effects on morphology and hyaluronic acid presentation.

    Almalik, Abdulaziz; Donno, Roberto; Cadman, Christopher J; Cellesi, Francesco; Day, Philip J; Tirelli, Nicola

    2013-12-28

    Chitosan nanoparticles are popular carriers for the delivery of macromolecular payloads, e.g. nucleic acids. In this study, nanoparticles were prepared via complexation with triphosphate (TPP) anions and were successively coated with hyaluronic acid (HA). Key variables of the preparative process (e.g. chitosan and HA molecular weight) were optimised in view of the maximisation of loading with DNA, of the Zeta potential and of the dimensional stability, and the resulting particles showed excellent storage stability. We have focused on the influence of chitosan molecular weight on nanoparticle properties. Larger molecular weight increased their porosity (=decreased cross-link density), and this caused also larger dimensional changes in response to variations in osmotic pressure or upon drying. The dependency of nanoparticle porosity on chitosan molecular weight had a profound effect on the adsorption of HA on the nanoparticles; HA was apparently able to penetrate deeply into the more porous high molecular weight (684 kDa) chitosan nanoparticles, while it formed a corona around those composed of more densely cross-linked low molecular weight (25 kDa) chitosan. Atomic Force Microscopy (AFM) allowed not only to highlight the presence of this corona, but also to estimate its apparent thickness to about 20-30 nm (in a dry state). The different morphology has a significant effect on the way HA is presented to biomolecules, and this has specific relevance in relation to interactions with HA receptors (e.g. CD44) that influence kinetics and mechanism of nanoparticle uptake. Finally, it is worth to mention that chitosan molecular weight did not appear to greatly affect the efficiency of nanoparticle loading with DNA, but significantly influenced its chitosanase-triggered release, with high molecular chitosan nanoparticles seemingly more prone to degradation by this enzyme. © 2013.

  4. Size and shape of soil humic acids estimated by viscosity and molecular weight.

    Kawahigashi, Masayuki; Sumida, Hiroaki; Yamamoto, Kazuhiko

    2005-04-15

    Ultrafiltration fractions of three soil humic acids were characterized by viscometry and high performance size-exclusion chromatography (HPSEC) in order to estimate shapes and hydrodynamic sizes. Intrinsic viscosities under given solute/solvent/temperature conditions were obtained by extrapolating the concentration dependence of reduced viscosities to zero concentration. Molecular mass (weight average molecular weight (M (w)) and number average molecular weight (M (n))) and hydrodynamic radius (R(H)) were determined by HPSEC using pullulan as calibrant. Values of M (w) and M (n) ranged from 15 to 118 x 10(3) and from 9 to 50 x 10(3) (g mol(-1)), respectively. Polydispersity, as indicated by M (w)/M (n), increased with increasing filter size from 1.5 to 2.4. The hydrodynamic radii (R(H)) ranged between 2.2 and 6.4 nm. For each humic acid, M (w) and [eta] were related. Mark-Houwink coefficients calculated on the basis of the M (w)-[eta] relationships suggested restricted flexible chains for two of the humic acids and a branched structure for the third humic acid. Those structures probably behave as hydrated sphere colloids in a good solvent. Hydrodynamic radii of fractions calculated from [eta] using Einstein's equation, which is applicable to hydrated sphere colloids, ranged from 2.2 to 7.1 nm. These dimensions are fit to the size of nanospaces on and between clay minerals and micropores in soil particle aggregates. On the other hand, the good agreement of R(H) values obtained by applying Einstein's equation with those directly determined by HPSEC suggests that pullulan is a suitable calibrant for estimation of molecular mass and size of humic acids by HPSEC.

  5. Effects of Hofmeister Anions on the LCST of PNIPAM as a Function of Molecular Weight

    Zhang, Yanjie; Furyk, Steven; Sagle, Laura B.; Cho, Younhee; Bergbreiter, David E.; Cremer, Paul S.

    2008-01-01

    The effect of a series of sodium salts on the lower critical solution temperature (LCST) of poly(N-isopropylacrylamide), PNIPAM, was investigated as a function of molecular weight and polymer concentration with a temperature gradient microfluidic device under a dark-field microscope. In solutions containing sufficient concentrations of kosmotropic anions, the phase transition of PNIPAM was resolved into two separate steps for higher molecular weight samples. The first step of this two step transition was found to be sensitive to the polymer’s molecular weight and solution concentration, while the second step was not. Moreover, the binding of chaotropic anions to the polymer was also influenced by molecular weight. Both sets of results could be explained by the formation of intramolecular and intermolecular hydrogen-bonding between polymer chains. By contrast, the hydrophobic hydration of the isopropyl moieties and polymer backbone was found to be unaffected by either the polymer’s molecular weight or solution concentration. PMID:18820735

  6. Preparation of Low Molecular Weight Gelatin Using Microwave Discharge Electrodeless Lamp/TiO2 Photocatalyst Hybrid System.

    Lee, Do-Jin; Kim, Hangun; Park, Young-Kwon; Kim, Byung Hoon; Lee, Heon; Jungf, Sana-Chul

    2016-02-01

    In this study, an MDEL/TiO2 photocatalyst hybrid system was applied to the production of low molecular weight gelatin. The molecular weight of produed gelatin decreased with increasing microwave intensity and increasing treatment time. The abscission of the chemical bonds between the con- stituents of gelatin by photocatalytic reaction did not alter the characteristics of gelatin. Formation of any by-products due to side reaction was not observed. It is suggested that gelatin was depolymerized by hydroxyl radicals produced during the MDEL/TiO2 photochemical reaction.

  7. Dextran: Influence of Molecular Weight in Antioxidant Properties and Immunomodulatory Potential.

    Soeiro, Vinicius C; Melo, Karoline R T; Alves, Monique G C F; Medeiros, Mayara J C; Grilo, Maria L P M; Almeida-Lima, Jailma; Pontes, Daniel L; Costa, Leandro S; Rocha, Hugo A O

    2016-08-19

    Dextrans (α-d-glucans) extracted from Leuconostoc mesenteroides, with molecular weights (MW) of 10 (D10), 40 (D40) and 147 (D147) kDa, were evaluated as antioxidant, anticoagulant and immunomodulatory drugs for the first time. None presented anticoagulant activity. As for the antioxidant and immunomodulatory tests, a specific test showed an increase in the dextran activity that was proportional to the increase in molecular weight. In a different assay, however, activity decreased or showed no correlation to the MW. As an example, the reducing power assay showed that D147 was twice as potent as other dextrans. On the other hand, all three samples showed similar activity (50%) when it came to scavenging the OH radical, whereas only the D10 sample showed sharp activity (50%) when it came to scavenging the superoxide ion. D40 was the single dextran that presented with immunomodulatory features since it stimulated the proliferation (~50%) of murine macrophages (RAW 264.7) and decreased the release of nitric oxide (~40%) by the cells, both in the absence and presence of lipopolysaccharides (LPS). In addition, D40 showed a greater scavenging activity (50%) for the hydrogen peroxide, which caused it to also be the more potent dextran when it came to inhibiting lipid peroxidation (70%). These points toward dextrans with a 40 kDa weight as being ideal for antioxidant and immunomodulatory use. However, future studies with the D40 and other similarly 40 kDa dextrans are underway to confirm this hypothesis.

  8. Removal of Anabaena spiroides by potassium permanganate pre-oxidation: effect on photosynthetic capacity and molecular weight distribution.

    Qiao, Junlian; Zhang, Xiaodong; Lv, Liping

    2017-11-01

    Bench scale tests were conducted to investigate the effect of potassium permanganate pre-oxidation on the photosynthetic activity and molecular weight distribution of Anabaena spiroides. Different concentrations of potassium permanganate were added into the suspension of Anabaena spiroides, one of the dominant algae in water bloom, and after pre-oxidation of permanganate for 1 h, the results show that the removal rate significantly increases by 33.99~36.35% compared to direct coagulation. Then, the algal characteristics, including photosynthetic ability, the changes in extracellular organic matter three-dimensional fluorescence, and the distribution of molecular weight were conducted and the results show that along with increasing concentration of potassium permanganate, the photosynthetic ability of algae decreases, more extracellular organic matter is secreted, and large molecular weight matter (humic-like and fulvic-like substances) are generated. Therefore, this study demonstrates that potassium permanganate could be used in addressing the algae-rich water.

  9. Enzymatic and acidic degradation of high molecular weight dextran into low molecular weight and its characterizations using novel Diffusion-ordered NMR spectroscopy.

    Iqbal, Samina; Marchetti, Roberta; Aman, Afsheen; Silipo, Alba; Qader, Shah Ali Ul; Molinaro, Antonio

    2017-10-01

    Low molecular weight fractions were derived from native high molecular weight dextran produced by Leuconostoc mesenteroides KIBGE-IB26. Structural characterization of native and low molecular weight fractions obtained after acidic and enzymatic hydrolysis was done using FTIR and NMR spectroscopy. The molecular weight was estimated using Diffusion Ordered NMR spectroscopy. Native dextran (892kDa) is composed of α-(1→6) glycosidic linkage along with α-(1→3) branching. Major proportion of 528kDa dextran was obtained after prolong enzymatic hydrolysis however, an effective acidic treatment at pH-1.4 up to 02 and 04h of exposure resulted in the formation of 77kDa and 57kDa, respectively. The increment in pH from 1.4 to 1.8 lowered the hydrolysis efficiency and resulted in the formation of 270kDa dextran fraction. The results suggest that derived low molecular weight water soluble fractions can be utilized as a drug delivery carrier along with multiple application relating pharmaceutical industries. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Functional Comparison for Lipid Metabolism and Intestinal and Fecal Microflora Enzyme Activities between Low Molecular Weight Chitosan and Chitosan Oligosaccharide in High-Fat-Diet-Fed Rats.

    Chiu, Chen-Yuan; Feng, Shih-An; Liu, Shing-Hwa; Chiang, Meng-Tsan

    2017-07-24

    The present study investigated and compared the regulatory effects on the lipid-related metabolism and intestinal disaccharidase/fecal bacterial enzyme activities between low molecular weight chitosan and chitosan oligosaccharide in high-fat-diet-fed rats. Diet supplementation of low molecular weight chitosan showed greater efficiency than chitosan oligosaccharide in suppressing the increased weights in body and in liver and adipose tissues of high-fat-diet-fed rats. Supplementation of low molecular weight chitosan also showed a greater improvement than chitosan oligosaccharide in imbalance of plasma, hepatic, and fecal lipid profiles, and intestinal disaccharidase activities in high-fat-diet-fed rats. Moreover, both low molecular weight chitosan and chitosan oligosaccharide significantly decreased the fecal microflora mucinase and β-glucuronidase activities in high-fat-diet-fed rats. These results suggest that low molecular weight chitosan exerts a greater positive improvement than chitosan oligosaccharide in lipid metabolism and intestinal disaccharidase activity in high-fat-diet-induced obese rats.

  11. Temporal trends in pregnancy weight gain and birth weight in Bavaria 2000–2007: slightly decreasing birth weight with increasing weight gain in pregnancy

    Schiessl, Barbara; Beyerlein, Andreas; Lack, Nicholas; Kries, Rüdiger von

    2009-01-01

    Aims: To assess temporal trends in birth weight and pregnancy weight gain in Bavaria from 2000 to 2007. Methods: Data on 695,707 mother and infant pairs (singleton term births) were available from a compulsory reporting system for quality assurance, including information on birth weight, maternal weight at delivery and at booking, maternal smoking, age, and further anthropometric and lifestyle factors. Pregnancy weight gain was defined as: weight prior to delivery minus weight at first booki...

  12. Use of Brazilian clay in nylon 6 with different molecular weight nanocomposites

    Araujo, Edcleide Maria; Paz, Rene Anisio; Melo, Tomas Jeferson Alves; Leite, Amanda Melissa Damiao; Barbosa, Renata; Ito, Edson Noriyuki

    2009-01-01

    The effect of nylon 6 (Ny6) molecular weight on the development of polymer/layered silicates nanocomposites prepared by the melt intercalation technique was studied in this work. The nylon6/organoclay nanocomposites were prepared in the counter-rotational twin screw extruder. The results of torque rheometry showed that the presence of organoclay in the nylon 6 increased the torque. The results of X-ray diffraction (XRD) and transmission electron microscopy (TEM) showed exfoliated and/or partially exfoliated structures. (author)

  13. The impact of treatment density and molecular weight for fractional laser-assisted drug delivery

    Haak, Christina S; Bhayana, Brijesh; Farinelli, William A

    2012-01-01

    Ablative fractional lasers (AFXL) facilitate uptake of topically applied drugs by creating narrow open micro-channels into the skin, but there is limited information on optimal laser settings for delivery of specific molecules. The objective of this study was to investigate the impact of laser...... treatment density (% of skin occupied by channels) and molecular weight (MW) for fractional CO(2) laser-assisted drug delivery. AFXL substantially increased intra- and transcutaneous delivery of polyethylene glycols (PEGs) in a MW range from 240 to 4300 Da (Nuclear Magnetic Resonance, p...

  14. Modulatory effect of high molecular weight polyethylene glycols on ...

    ADOWIE PERE

    (MW 4000 and 6000) on drug release from ibuprofen sustained release formulation. Different batches of .... tapped density that is the ratio of the weight of the granules and the ..... conferring less resistance to tablet fracture and abrasion.

  15. Increased body weight affects academic performance in university students

    Angela S. Anderson

    2017-03-01

    Full Text Available For K-12 students, obesity has been linked to student educational achievements. The study objective was to determine whether academic performance in university students is correlated with BMI. Students from two consecutive academic years (Jan–May 2013 and Jan–May 2014 were given an optional class survey in May, as extra credit. Of the 452 students that completed the survey, 204 females and 75 males (N = 279; 73% female and 27% male consented to participate in the study. The number of correct answers to problem-solving questions (PSQs and the overall final grade for the class were compared to the calculated BMI using linear regression with a Pearson's R correlation and unpaired t-tests. BMI was significantly negatively correlated with student's final grades (P = 0.001 Pearson's r = −0.190 and PSQs were positively correlated with final grades (P < 0.001; Pearson's r = 0.357. Our findings show a correlation between healthy body weight and improved academic performance. Further, the data suggest that future research in the area of body weight, diet, and exercise and any correlations of these with academic performance in college students are warranted.

  16. Effect of gamma irradiation on the friction and wear of ultrahigh molecular weight polyethylene

    Jones, W. R.; Hady, W. F.; Crugnola, A.

    1981-01-01

    The effect of sterilization gamma irradiation on the friction and wear properties of ultrahigh molecular weight polyethylene (UHMWPE) sliding against stainless steel 316L in dry air at 23 C is investigated, the results to be used in the development of artificial joints which are to surgically replace diseased human joints. A pin-on-disk sliding friction apparatus is used, a constant sliding speed in the range 0.061-0.27 m/s is maintained, a normal load of 1 kgf is applied with dead weight, and the irradiation dose levels are: 0, 2.5, and 5.0 Mrad. Wear and friction data and conditions for each of the ten tests are summarized, and include: (1) wear volume as a function of the sliding distance for the irradiation levels, (2) incremental wear rate, and (3) coefficient of friction as a function of the sliding distance. It is shown that (1) the friction and wear properties of UHMWPE are not significantly changed by the irradiation doses of 2.5 and 5.0 Mrad, (2) the irradiation increases the amount of insoluble gel as well as the amount of low molecular weight material, and (3) after run-in the wear rate is either steady or gradually decreases as a function of the sliding distance.

  17. Effect of molecular weight distribution on e-beam exposure properties of polystyrene

    Dey, Ripon Kumar; Cui Bo

    2013-01-01

    Polystyrene is a negative electron beam resist whose exposure properties can be tuned simply by using different molecular weights (Mw). Most previous studies have used monodisperse polystyrene with a polydispersity index (PDI) of less than 1.1 in order to avoid any uncertainties. Here we show that despite the fact that polystyrene’s sensitivity is inversely proportional to its Mw, no noticeable effect of very broad molecular weight distribution on sensitivity, contrast and achievable resolution is observed. It is thus unnecessary to use the costly monodisperse polystyrene for electron beam lithography. Since the polydispersity is unknown for general purpose polystyrene, we simulated a high PDI polystyrene by mixing in a 1:1 weight ratio two polystyrene samples with Mw of 170 and 900 kg mol −1 for the high Mw range, and 2.5 and 13 kg mol −1 for the low Mw range. The exposure property of the mixture resembles that of a monodisperse polystyrene with similar number averaged molecular weight (Mn)-bar, which indicates that it is (Mn)-bar rather than (Mw)-bar (weight averaged molecular weight) that dominates the exposure properties of polystyrene resist. This also implies that polystyrene of a certain molecular weight can be simulated by a mixture of two polystyrenes having different molecular weights. (paper)

  18. Increasing low birth weight rates: deliveries in a tertiary hospital in istanbul.

    Akin, Yasemin; Cömert, Serdar; Turan, Cem; Unal, Orhan; Piçak, Abdülkadir; Ger, Lale; Telatar, Berrin

    2010-09-01

    Prevalence of low birth weight deliveries may vary across different environments. The necessity of determination of regional data prompted this study. Information of all deliveries from January 2004 to December 2008 was obtained from delivery registry records retrospectively. Initial data including birth weight, vital status, sex, maternal age and mode of delivery were recorded using medical files. The frequency of low birth weight, very low birth weight, extremely low birth weight and stillbirth deliveries were determined. Among 19,533 total births, there were 450 (23.04 per 1000) stillbirths. Low birth weight rate was 10.61%. A significant increase in yearly distribution of low birth weight deliveries was observed (Pbirth weight and extremely low birth weight delivery rates were 3.14% and 1.58% respectively. Among 2073 low birth weight infants, 333 (16.06%) were stillbirths. The stillbirth delivery rate and the birth of a female infant among low birth weight deliveries were significantly higher than infants with birth weight ≥2500g (Pbirth weight and maternal age. The rate of cesarean section among low birth weight infants was 49.4%. High low birth weight and stillbirth rates, as well as the increase in low birth weight deliveries over the past five years in this study are striking. For reduction of increased low birth weight rates, appropriate intervention methods should be initiated.

  19. Molecular Weight Effects on the Glass Transition and Confinement Behavior of Polymer Thin Films.

    Xia, Wenjie; Hsu, David D; Keten, Sinan

    2015-08-01

    Nanoscale polymer thin films exhibit strong confinement effects on Tg arising from free surfaces. However, the coupled influence of molecular weight (MW) and surface effects on Tg is not well understood for low MW film systems below the entanglement length. Utilizing atomistically informed coarse-grained molecular dynamics simulations for poly(methyl methacrylate) (PMMA), it is demonstrated that the decrease in free-standing film Tg with respect to bulk is more significant for low MW compared to high MW systems. Investigation of the local interfacial properties reveals that the increase in the local free volume near the free surface is greater for low MW, explaining the MW dependence of Tg -confinement behaviors. These findings corroborate recent experiments on low MW films, and highlight the relationship between nanoconfinement phenomena and local free volume effects arising from free surfaces. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Detection of high molecular weight proteins by MALDI imaging mass spectrometry.

    Mainini, Veronica; Bovo, Giorgio; Chinello, Clizia; Gianazza, Erica; Grasso, Marco; Cattoretti, Giorgio; Magni, Fulvio

    2013-06-01

    MALDI imaging mass spectrometry (IMS) is a unique technology to explore the spatial distribution of biomolecules directly on tissues. It allows the in situ investigation of a large number of small proteins and peptides. Detection of high molecular weight proteins through MALDI IMS still represents an important challenge, as it would allow the direct investigation of the distribution of more proteins involved in biological processes, such as cytokines, enzymes, neuropeptide precursors and receptors. In this work we compare the traditional method performed with sinapinic acid with a comparable protocol using ferulic acid as the matrix. Data show a remarkable increase of signal acquisition in the mass range of 20k to 150k Th. Moreover, we report molecular images of biomolecules above 70k Th, demonstrating the possibility of expanding the application of this technology both in clinical investigations and basic science.

  1. Equal channel angular extrusion of ultra-high molecular weight polyethylene

    Reinitz, Steven D., E-mail: Steven.D.Reinitz.TH@Dartmouth.edu; Engler, Alexander J.; Carlson, Evan M.; Van Citters, Douglas W.

    2016-10-01

    Ultra-high molecular weight polyethylene (UHMWPE), a common bearing surface in total joint arthroplasty, is subject to material property tradeoffs associated with conventional processing techniques. For orthopaedic applications, radiation-induced cross-linking is used to enhance the wear resistance of the material, but cross-linking also restricts relative chain movement in the amorphous regions and hence decreases toughness. Equal Channel Angular Extrusion (ECAE) is proposed as a novel mechanism by which entanglements can be introduced to the polymer bulk during consolidation, with the aim of imparting the same tribological benefits of conventional processing without complete inhibition of chain motion. ECAE processing at temperatures near the crystalline melt for UHMWPE produces (1) increased entanglements compared to control materials; (2) increasing entanglements with increasing temperature; and (3) mechanical properties between values for untreated polyethylene and for cross-linked polyethylene. These results support additional research in ECAE-processed UHMWPE for joint arthroplasty applications. - Highlights: • A new processing method for ultra-high molecular weight polyethylene is introduced. • The process produces a highly entangled polyethylene material. • Entanglements are hypothesized to enhance the wear resistance of polyethylene. • This process eliminates the trade-off between mechanical and wear properties.

  2. Determination of viscosity-average molecular weight of chitosan using intrinsic viscosity measurement

    Norzita Yacob; Norhashidah Talip; Maznah Mahmud; Nurul Aizam Idayu Mat Sani; Nor Akma Samsuddin; Norafifah Ahmad Fabillah

    2013-01-01

    Determination of molecular weight by intrinsic viscosity measurement is a simple method for characterization of chitosan. To study the effect of radiation on molecular weight, chitosan was first irradiated using electron beam at different doses prior to measurement. Different concentrations of chitosan were prepared and measurement was done at room temperature. The flow time data was used to calculate the intrinsic viscosity by extrapolating the reduced viscosity to zero concentration. The value of intrinsic viscosity was then recalculated into the viscosity-average molecular weight using Mark-Houwink equation. (Author)

  3. Preclinical studies of lymphographic applilcation of 99mTc-dextrans of different molecular weight

    Lamka, J.; Kvetina, J.; Kafka, P.

    1986-01-01

    In a preclinical investigation on rabbits the distribution was tested of dextrans of two molecular weights (40,000 and 70,000) with regard to their use as a carrier in indirect lymphography. The tests showed that both 99m Tc-dextrans achieve high ratios of lymph/blood levels. It is suggested that for clinical work it is better to use dextran with a molecular weight of 70,000 than that with a molecular weight of 40,000. (author)

  4. Role of Molecular Weight Distribution on Charge Transport in Semiconducting Polymers

    Himmelberger, Scott

    2014-10-28

    © 2014 American Chemical Society. Model semiconducting polymer blends of well-controlled molecular weight distributions are fabricated and demonstrated to be a simple method to control intermolecular disorder without affecting intramolecular order or degree of aggregation. Mobility measurements exhibit that even small amounts of low molecular weight material are detrimental to charge transport. Trends in charge carrier mobility can be reproduced by a simple analytical model which indicates that carriers have no preference for high or low molecular weight chains and that charge transport is limited by interchain hopping. These results quantify the role of long polymer tie-chains and demonstrate the need for controlled polydispersity for achieving high carrier mobilities.

  5. Determination of Viscosity-Average Molecular Weight of Chitosan using Intrinsic Viscosity Measurement

    Norzita Yacob; Norhashidah Talip; Maznah Mahmud

    2011-01-01

    Molecular weight of chitosan can be determined by different techniques such as Gel Permeation Chromatography (GPC), Static Light Scattering (SLS) and intrinsic viscosity measurement. Determination of molecular weight by intrinsic viscosity measurement is a simple method for characterization of chitosan. Different concentrations of chitosan were prepared and measurement was done at room temperature. The flow time data was used to calculate the intrinsic viscosity by extrapolating the reduced viscosity to zero concentration. The value of intrinsic viscosity was then recalculated into the viscosity-average molecular weight using Mark-Houwink equation. (author)

  6. Preparation of Low Molecular Weight Heparin by Microwave Discharge Electrodeless Lamp/TiO2 Photo-Catalytic Reaction.

    Lee, Do-Jin; Kim, Byung Hoon; Kim, Sun-Jae; Kim, Jung-Sik; Lee, Heon; Jung, Sang-Chul

    2015-01-01

    An MDEL/TiO2 photo-catalyst hybrid system was applied, for the first time, for the production of low molecular weight heparin. The molecular weight of produed heparin decreased with increasing microwave intensity and treatment time. The abscission of the chemical bonds between the constituents of heparin by photo-catalytic reaction did not alter the characteristics of heparin. Formation of by-products due to side reaction was not observed. It is suggested that heparin was depolymerized by active oxygen radicals produced during the MDEL/TiO2 photo-chemical reaction.

  7. Practical Application of Aptamer-Based Biosensors in Detection of Low Molecular Weight Pollutants in Water Sources

    Wei Zhang

    2018-02-01

    Full Text Available Water pollution has become one of the leading causes of human health problems. Low molecular weight pollutants, even at trace concentrations in water sources, have aroused global attention due to their toxicity after long-time exposure. There is an increased demand for appropriate methods to detect these pollutants in aquatic systems. Aptamers, single-stranded DNA or RNA, have high affinity and specificity to each of their target molecule, similar to antigen-antibody interaction. Aptamers can be selected using a method called Systematic Evolution of Ligands by EXponential enrichment (SELEX. Recent years we have witnessed great progress in developing aptamer selection and aptamer-based sensors for low molecular weight pollutants in water sources, such as tap water, seawater, lake water, river water, as well as wastewater and its effluents. This review provides an overview of aptamer-based methods as a novel approach for detecting low molecular weight pollutants in water sources.

  8. High Molecular Weight Forms of Mammalian Respiratory Chain Complex II

    Kovářová, Nikola; Mráček, Tomáš; Nůsková, Hana; Holzerová, Eliška; Vrbacký, Marek; Pecina, Petr; Hejzlarová, Kateřina; Klučková, Katarína; Rohlena, Jakub; Neužil, Jiří; Houštěk, Josef

    2013-01-01

    Roč. 8, č. 8 (2013), e71869 E-ISSN 1932-6203 R&D Projects: GA ČR(CZ) GPP303/10/P227; GA MŠk(CZ) LL1204; GA MZd(CZ) NT12370; GA ČR(CZ) GAP301/10/1937 Institutional research plan: CEZ:AV0Z50520701 Institutional support: RVO:67985823 Keywords : supercomplexes * high molecular weihgt forms of complex II * native electrophoretic systems Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.534, year: 2013

  9. Self-Directed Weight Loss Strategies: Energy Expenditure Due to Physical Activity Is Not Increased to Achieve Intended Weight Loss

    Ulf Elbelt

    2015-07-01

    Full Text Available Reduced physical activity and almost unlimited availability of food are major contributors to the development of obesity. With the decline of strenuous work, energy expenditure due to spontaneous physical activity has attracted increasing attention. Our aim was to assess changes in energy expenditure, physical activity patterns and nutritional habits in obese subjects aiming at self-directed weight loss. Methods: Energy expenditure and physical activity patterns were measured with a portable armband device. Nutritional habits were assessed with a food frequency questionnaire. Results: Data on weight development, energy expenditure, physical activity patterns and nutritional habits were obtained for 105 patients over a six-month period from an initial cohort of 160 outpatients aiming at weight loss. Mean weight loss was −1.5 ± 7.0 kg (p = 0.028. Patients with weight maintenance (n = 75, with substantial weight loss (>5% body weight, n = 20 and with substantial weight gain (>5% body weight, n = 10 did not differ in regard to changes of body weight adjusted energy expenditure components (total energy expenditure: −0.2 kcal/kg/day; non-exercise activity thermogenesis: −0.3 kcal/kg/day; exercise-related activity thermogenesis (EAT: −0.2 kcal/kg/day or patterns of physical activity (duration of EAT: −2 min/day; steps/day: −156; metabolic equivalent unchanged measured objectively with a portable armband device. Self-reported consumption frequency of unfavorable food decreased significantly (p = 0.019 over the six-month period. Conclusions: An increase in energy expenditure or changes of physical activity patterns (objectively assessed with a portable armband device are not employed by obese subjects to achieve self-directed weight loss. However, modified nutritional habits could be detected with the use of a food frequency questionnaire.

  10. Self-Directed Weight Loss Strategies: Energy Expenditure Due to Physical Activity Is Not Increased to Achieve Intended Weight Loss.

    Elbelt, Ulf; Schuetz, Tatjana; Knoll, Nina; Burkert, Silke

    2015-07-16

    Reduced physical activity and almost unlimited availability of food are major contributors to the development of obesity. With the decline of strenuous work, energy expenditure due to spontaneous physical activity has attracted increasing attention. Our aim was to assess changes in energy expenditure, physical activity patterns and nutritional habits in obese subjects aiming at self-directed weight loss. Energy expenditure and physical activity patterns were measured with a portable armband device. Nutritional habits were assessed with a food frequency questionnaire. Data on weight development, energy expenditure, physical activity patterns and nutritional habits were obtained for 105 patients over a six-month period from an initial cohort of 160 outpatients aiming at weight loss. Mean weight loss was -1.5 ± 7.0 kg (p = 0.028). Patients with weight maintenance (n = 75), with substantial weight loss (>5% body weight, n = 20) and with substantial weight gain (>5% body weight, n = 10) did not differ in regard to changes of body weight adjusted energy expenditure components (total energy expenditure: -0.2 kcal/kg/day; non-exercise activity thermogenesis: -0.3 kcal/kg/day; exercise-related activity thermogenesis (EAT): -0.2 kcal/kg/day) or patterns of physical activity (duration of EAT: -2 min/day; steps/day: -156; metabolic equivalent unchanged) measured objectively with a portable armband device. Self-reported consumption frequency of unfavorable food decreased significantly (p = 0.019) over the six-month period. An increase in energy expenditure or changes of physical activity patterns (objectively assessed with a portable armband device) are not employed by obese subjects to achieve self-directed weight loss. However, modified nutritional habits could be detected with the use of a food frequency questionnaire.

  11. Peptidylation for the determination of low-molecular-weight compounds by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

    Tang, Feng; Cen, Si-Ying; He, Huan; Liu, Yi; Yuan, Bi-Feng; Feng, Yu-Qi

    2016-05-23

    Determination of low-molecular-weight compounds by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) has been a great challenge in the analytical research field. Here we developed a universal peptide-based derivatization (peptidylation) strategy for the sensitive analysis of low-molecular-weight compounds by MALDI-TOF-MS. Upon peptidylation, the molecular weights of target analytes increase, thus avoiding serious matrix ion interference in the low-molecular-weight region in MALDI-TOF-MS. Since peptides typically exhibit good signal response during MALDI-TOF-MS analysis, peptidylation endows high detection sensitivities of low-molecular-weight analytes. As a proof-of-concept, we analyzed low-molecular-weight compounds of aldehydes and thiols by the developed peptidylation strategy. Our results showed that aldehydes and thiols can be readily determined upon peptidylation, thus realizing the sensitive and efficient determination of low-molecular-weight compounds by MALDI-TOF-MS. Moreover, target analytes also can be unambiguously detected in biological samples using the peptidylation strategy. The established peptidylation strategy is a universal strategy and can be extended to the sensitive analysis of various low-molecular-weight compounds by MALDI-TOF-MS, which may be potentially used in areas such as metabolomics.

  12. Enhancing Accuracy in Molecular Weight Determination of Highly Heterogeneously Glycosylated Proteins by Native Tandem Mass Spectrometry

    Wang, Guanbo; de Jong, Rob N; van den Bremer, Ewald T J; Parren, Paul W H I; Heck, Albert J R

    2017-01-01

    The determination of molecular weights (MWs) of heavily glycosylated proteins is seriously hampered by the physicochemical characteristics and heterogeneity of the attached carbohydrates. Glycosylation impacts protein migration during sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis

  13. Effect of soil sieving on respiration induced by low-molecular-weight substrates

    Datta, Rahul; Vranová, Valerie; Pavelka, Marian; Rejšek, Klement; Formánek, Pavel

    2014-03-01

    The mesh size of sieves has a significant impact upon soil disturbance, affecting pore structure, fungal hyphae, proportion of fungi to bacteria, and organic matter fractions. The effects are dependent upon soil type and plant coverage. Sieving through a 2 mm mesh increases mineralization of exogenously supplied carbohydrates and phenolics compared to a 5 mm mesh and the effect is significant (p<0.05), especially in organic horizons, due to increased microbial metabolism and alteration of other soil properties. Finer mesh size particularly increases arabinose, mannose, galactose, ferulic and pthalic acid metabolism, whereas maltose mineralization is less affected. Sieving through a 5 mm mesh size is suggested for all type of experiments where enhanced mineralization of low-molecular-weight organic compounds needs to be minimalized.

  14. Influences of gamma irradiation treatment on the molecular weight of chitosan

    Luu Thi Tho; Nguyen Viet Thong; Tran Minh Quynh; Vu Thi Hong Khanh

    2013-01-01

    Effects of gamma radiation on molecular properties of shrimp and squid chitosan (MTV, Vietnam) have been studied with three kind chitosan that having degree of deacetylation 75% and different molecular molecular weight of 69, 187 and 345 kDa, Chitosan samples were irradiated at the same dose rate of 4.3 kGy per hour with various radiation dose of 25, 50, 75, 100, 200 and 500 kGy. The viscosity average molecular weight and degree of deacetylation (DD) of chitosan before and after irradiation have been investigated via their intrinsic viscosity and Furrier transform infra-red (FT-IR). The data revealed the chitosan backbone chains has been degraded by gamma radiation, resulting in the smaller fragments with reduced molecular weight to 3000 Da, whereas their DD have not much changed. (author)

  15. Nitrogen mineralization in a simulated rhizosphere as influenced by low molecular weight organic substances

    Begum, Shamim Ara; Kader, MD Abdul; Sleutel, Steven; De Neve, Stefaan

    2012-01-01

    Rhizodeposits consist of over 200 organic compounds, mainly low-molecular-weight organic substances (LMWOS) such as amino acids (AA), carbohydrates (CH) and carboxylic acids (CA), lipids and phenols. Those LMWOS influence nutrient turnover, particularly N turnover. However, the exact influence of these organic substances on nitrogen mineralization is yet unknown. Therefore, the stimulatory effects of low molecular weight organic substances on nitrogen mineralization in the rhizosphere of a si...

  16. OBSERVATION ON INCREASE IN WEIGHT OF LOW BIRTH WEIGHT (LBW BABIES BY IMPLEMENTING KANGAROO MOTHER CARE (KMC TECHNIQUE

    Purnendu Kumar Singh

    2014-12-01

    Full Text Available Kangaroo Mother Care (KMC is a practical technique for nursing of low birth weight babies by direct skin to contact with the mother. This study was undertaken to observe and record the effect of KMC with focus on increase in weight of at term low birth weight (LBW babies weighing less than 2000 grams. The study was conducted over thirty six month’s period from July 2011 to June 2014. The method of care consisted of skin to skin contact between the mother and the infant along with exclusive breast milk. Upon implementation of KMC babies under observation showed satisfactory gain in weight of average 25grams per day and an average hospital stay of 10 days. KMC aims towards achieving good weight gain in LBW babies. It is a simple hassle free technique which can be implemented at all levels of health care.

  17. Increased Body Weight Reduces Voluntary Movement to Maintain Energy Expenditure of Rats Exposed to Increases in Gravity

    Wade, C. E.; Moran, M. M.; Stein, T. P.; Sin, Sidney (Technical Monitor)

    2001-01-01

    With the increase in obesity related diseases there is heightened interest in mechanisms regulating body weight. To assess the influence of increases in body weight on energy expenditure and intake in rats we employed variable levels of gravity. Our approach afforded the means to measure interactions of energy expenditure and intake in response to increases in body weight (body mass x gravity level). We found a dose relationship between rapid elevation of body weight and reduction of voluntary movement, such that the energy requirements for activity are unchanged, and total energy expenditure and intake maintained. Reduction of movement appears to be a response to increased body weight, rather than a contributing factor, suggesting a new regulatory pathway.

  18. Effects of ionizing radiation on the properties of ultra-high molecular weight polyethylene (PE-UHMW)

    Kurth, M.

    1990-01-01

    Ultra high molecular weight polyethylene (PE-UHMW) is used in most artificial joint replacement devices. Prior to implantation in biological environment, radiatin sterilization by 60 Co or electron beam is common. It is well known that polyethylene exposed to ionizing radiation of any sort undergo physical changes due to chain scission and/or crosslinking. PE-UHMW sheets, 8 mm thick, were either 60 Co or electron beam irradiated, in the range of 10-150 kGy under air or nitrogen atmoshere. The crystallinity of the irradiated samples increases with the irradiation dose. The chain scission/crosslinking events ratio determine the network structure and the sol/gel ratio. The latter was found to depend on irradiation dose, radiation atmosphere and sample thickness. Moreover 60 Co-irradiation is about 5 times more effective in forming PE-UHMW gel than electron-irradiation. Besides the degree of crosslinking, the molecular weight distribution is the main determinant of the structural properties of PE-UHMW. Low molecular weight fractions were also found. Using a dose of 30 kGy ( 60 Co in air), the average molecular weight of the soluble part after extraction decreased from originally 2.3 million g/mol to 170.000 g/mol, corresponding to a factor of about 10. These changes in molecular weight have a strong influence on the mechanical properties of PE-UHMW. Crosslinking slightly increases the yield strength, while the elongation at break decreases. Long-term compressive creep is reduced if the material is irradiated. Obviously, increased crystallinity after oxidative chain scission affects a higher deformation resistance. Radiation crosslinked structures cause a significant increase in abrasion resistance. The above described structural changes occur even upon irradiation of very low doses as used during sterilization. This study will enable to reduce the radiation sterilization damage and thus to gain long term stability of PE-UHMW medical devices. (orig./BBR)

  19. OBSERVATION ON INCREASE IN WEIGHT OF LOW BIRTH WEIGHT (LBW) BABIES BY IMPLEMENTING KANGAROO MOTHER CARE (KMC) TECHNIQUE

    Purnendu Kumar Singh; Kumar Amritanshu; Bijoy Mukherjee

    2014-01-01

    Kangaroo Mother Care (KMC) is a practical technique for nursing of low birth weight babies by direct skin to contact with the mother. This study was undertaken to observe and record the effect of KMC with focus on increase in weight of at term low birth weight (LBW) babies weighing less than 2000 grams. The study was conducted over thirty six month’s period from July 2011 to June 2014. The method of care consisted of skin to skin contact between the mother and the infant along ...

  20. Study of effect of gamma radiation on molecular weight and mechanical properties of PHB and PHNV

    Fechine, Guilhermino J.M.; Terence, Mauro C.; Rabello, M.S.; Willen, Renate M.R.

    2011-01-01

    The effect of gamma radiation on molecular weight and mechanical properties (tensile and flexural) of PHB and PHBV samples was investigated. The values of stress and strain at the break point for both mechanical properties indicated that scission molecular reactions were predominant in PHB and PHBV samples submitted to gamma radiation. These results were confirmed by Size Exclusion Chromatography (SEC) analysis. (author)

  1. Use of Kinematic Viscosity Data for the Evaluation of the Molecular Weight of Petroleum Oils

    Maroto, J. A.; Quesada-Perez, M.; Ortiz-Hernandez, A. J.

    2010-01-01

    A new laboratory procedure for the evaluation of the mean molecular weight (mean relative molecular mass) of petroleum oils with high accuracy is described. The density and dynamic viscosity of three commercial petroleum oils are measured at different temperatures. These experimental data are used to calculate the kinematic viscosity as a function…

  2. The Value of a General Increase in Slaughter Weight for Pigs

    Kjærsgaard, Niels Christian

    of Danish pig production, slaughtering processes and delivery. There have been varying opinions within the industry concerning an improved profit for the slaughterhouses and the farmers when increasing the slaughter weight. The argument for an increased slaughter weight is based on the fact that some...... different weight scenarios, namely the current slaughter weight as well as increases in the slaughter weight of 5, 10 and 15 kg respectively. The model set up in this paper consists of 17 different products and four alternative uses of each pig, but the model can easily be changed to include more products...... to approximately DKK 0.25 for each increase in slaughter weight of 5 kg. The main conclusion is that even relatively simple optimization models can be used to improve the basis of the slaughterhouses considerably for making decisions regarding the value of increased slaughter weight. Prices may vary over time...

  3. Effects of molecular weight on the glass transition temperature in Durolon polycarbonate; Os efeitos da massa molecular sobre a temperatura de transicao vitrea (Tg) para o policarbonato Durolon

    Miranda, Adelina; Sciani, Valdir [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

    1995-12-31

    The effect of variation of the dose rate on degradation mechanism of PC Durolon irradiated with gamma rays was determined trough out intrinsic viscosity and thermal analysis of DSC-type measurements. The results showed a linear relationship between the glass transition temperature and the viscosimetric average molecular weight. From the results it`s shown that with an increased of the dose rate it also increases the degradation of the material. (author). 12 refs., 3 figs.

  4. Extraction of High Molecular Weight DNA from Fungal Rust Spores for Long Read Sequencing.

    Schwessinger, Benjamin; Rathjen, John P

    2017-01-01

    Wheat rust fungi are complex organisms with a complete life cycle that involves two different host plants and five different spore types. During the asexual infection cycle on wheat, rusts produce massive amounts of dikaryotic urediniospores. These spores are dikaryotic (two nuclei) with each nucleus containing one haploid genome. This dikaryotic state is likely to contribute to their evolutionary success, making them some of the major wheat pathogens globally. Despite this, most published wheat rust genomes are highly fragmented and contain very little haplotype-specific sequence information. Current long-read sequencing technologies hold great promise to provide more contiguous and haplotype-phased genome assemblies. Long reads are able to span repetitive regions and phase structural differences between the haplomes. This increased genome resolution enables the identification of complex loci and the study of genome evolution beyond simple nucleotide polymorphisms. Long-read technologies require pure high molecular weight DNA as an input for sequencing. Here, we describe a DNA extraction protocol for rust spores that yields pure double-stranded DNA molecules with molecular weight of >50 kilo-base pairs (kbp). The isolated DNA is of sufficient purity for PacBio long-read sequencing, but may require additional purification for other sequencing technologies such as Nanopore and 10× Genomics.

  5. Phase behaviour of oat β-glucan/sodium caseinate mixtures varying in molecular weight.

    Agbenorhevi, Jacob K; Kontogiorgos, Vassilis; Kasapis, Stefan

    2013-05-01

    The isothermal phase behaviour at 5 °C of mixtures of sodium caseinate and oat β-glucan isolates varying in molecular weight (MW) was investigated by means of phase diagram construction, rheometry, fluorescence microscopy and electrophoresis. Phase diagrams indicated that the compatibility of the β-glucan/sodium caseinate system increases as β-glucan MW decreases. Images of mixtures taken at various biopolymer concentrations revealed phase separated domains. Results also revealed that at the state of thermodynamic equilibrium, lower MW samples yielded considerable viscosity in the mixture. At equivalent hydrodynamic volume of β-glucan in the mixtures, samples varying in molecular weight exhibited similar flow behaviour. A deviation dependent on the protein concentration was observed for the high MW sample in the concentrated regime due to the size of β-glucan aggregates formed. Results demonstrate that by controlling the structural features of β-glucan in mixtures with sodium caseinate, informed manipulation of rheological properties in these systems can be achieved. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Exploiting Molecular Weight Distribution Shape to Tune Domain Spacing in Block Copolymer Thin Films.

    Gentekos, Dillon T; Jia, Junteng; Tirado, Erika S; Barteau, Katherine P; Smilgies, Detlef-M; DiStasio, Robert A; Fors, Brett P

    2018-04-04

    We report a method for tuning the domain spacing ( D sp ) of self-assembled block copolymer thin films of poly(styrene- block-methyl methacrylate) (PS- b-PMMA) over a large range of lamellar periods. By modifying the molecular weight distribution (MWD) shape (including both the breadth and skew) of the PS block via temporal control of polymer chain initiation in anionic polymerization, we observe increases of up to 41% in D sp for polymers with the same overall molecular weight ( M n ≈ 125 kg mol -1 ) without significantly changing the overall morphology or chemical composition of the final material. In conjunction with our experimental efforts, we have utilized concepts from population statistics and least-squares analysis to develop a model for predicting D sp based on the first three moments of the MWDs. This statistical model reproduces experimental D sp values with high fidelity (with mean absolute errors of 1.2 nm or 1.8%) and provides novel physical insight into the individual and collective roles played by the MWD moments in determining this property of interest. This work demonstrates that both MWD breadth and skew have a profound influence over D sp , thereby providing an experimental and conceptual platform for exploiting MWD shape as a simple and modular handle for fine-tuning D sp in block copolymer thin films.

  7. Effects of inhaled high-molecular weight hyaluronan in inflammatory airway disease.

    Lamas, Adelaida; Marshburn, Jamie; Stober, Vandy P; Donaldson, Scott H; Garantziotis, Stavros

    2016-10-03

    Cystic fibrosis (CF) is a chronic inflammatory disease that is affecting thousands of patients worldwide. Adjuvant anti-inflammatory treatment is an important component of cystic fibrosis treatment, and has shown promise in preserving lung function and prolonging life expectancy. Inhaled high molecular weight hyaluronan (HMW-HA) is reported to improve tolerability of hypertonic saline and thus increase compliance, and has been approved in some European countries for use as an adjunct to hypertonic saline treatment in cystic fibrosis. However, there are theoretical concerns that HMW-HA breakdown products may be pro-inflammatory. In this clinical pilot study we show that sputum cytokines in CF patients receiving HMW-HA are not increased, and therefore HMW-HA does not appear to adversely affect inflammatory status in CF airways.

  8. High Pressure Size Exclusion Chromatography (HPSEC) Determination of Dissolved Organic Matter Molecular Weight Revisited: Accounting for Changes in Stationary Phases, Analytical Standards, and Isolation Methods.

    McAdams, Brandon C; Aiken, George R; McKnight, Diane M; Arnold, William A; Chin, Yu-Ping

    2018-01-16

    We reassessed the molecular weight of dissolved organic matter (DOM) determined by high pressure size exclusion chromatography (HPSEC) using measurements made with different columns and various generations of polystyrenesulfonate (PSS) molecular weight standards. Molecular weight measurements made with a newer generation HPSEC column and PSS standards from more recent lots are roughly 200 to 400 Da lower than initial measurements made in the early 1990s. These updated numbers match DOM molecular weights measured by colligative methods and fall within a range of values calculated from hydroxyl radical kinetics. These changes suggest improved accuracy of HPSEC molecular weight measurements that we attribute to improved accuracy of PSS standards and changes in the column packing. We also isolated DOM from wetlands in the Prairie Pothole Region (PPR) using XAD-8, a cation exchange resin, and PPL, a styrene-divinylbenzene media, and observed little difference in molecular weight and specific UV absorbance at 280 nm (SUVA 280 ) between the two solid phase extraction resins, suggesting they capture similar DOM moieties. PPR DOM also showed lower SUVA 280 at similar weights compared to DOM isolates from a global range of environments, which we attribute to oxidized sulfur in PPR DOM that would increase molecular weight without affecting SUVA 280 .

  9. High pressure size exclusion chromatography (HPSEC) determination of dissolved organic matter molecular weight revisited: Accounting for changes in stationary phases, analytical standards, and isolation methods

    McAdams, Brandon C.; Aiken, George R.; McKnight, Diane M.; Arnold, William A.; Chin, Yu-Ping

    2018-01-01

    We reassessed the molecular weight of dissolved organic matter (DOM) determined by high pressure size exclusion chromatography (HPSEC) using measurements made with different columns and various generations of polystyrenesulfonate (PSS) molecular weight standards. Molecular weight measurements made with a newer generation HPSEC column and PSS standards from more recent lots are roughly 200 to 400 Da lower than initial measurements made in the early 1990s. These updated numbers match DOM molecular weights measured by colligative methods and fall within a range of values calculated from hydroxyl radical kinetics. These changes suggest improved accuracy of HPSEC molecular weight measurements that we attribute to improved accuracy of PSS standards and changes in the column packing. We also isolated DOM from wetlands in the Prairie Pothole Region (PPR) using XAD-8, a cation exchange resin, and PPL, a styrene-divinylbenzene media, and observed little difference in molecular weight and specific UV absorbance at 280 nm (SUVA280) between the two solid phase extraction resins, suggesting they capture similar DOM moieties. PPR DOM also showed lower SUVA280 at similar weights compared to DOM isolates from a global range of environments, which we attribute to oxidized sulfur in PPR DOM that would increase molecular weight without affecting SUVA280.

  10. Profiling of the Molecular Weight and Structural Isomer Abundance of Macroalgae-Derived Phlorotannins

    Natalie Heffernan

    2015-01-01

    Full Text Available Phlorotannins are a group of complex polymers of phloroglucinol (1,3,5-trihydroxybenzene unique to macroalgae. These phenolic compounds are integral structural components of the cell wall in brown algae, but also play many secondary ecological roles such as protection from UV radiation and defense against grazing. This study employed Ultra Performance Liquid Chromatography (UPLC with tandem mass spectrometry to investigate isomeric complexity and observed differences in phlorotannins derived from macroalgae harvested off the Irish coast (Fucus serratus, Fucus vesiculosus, Himanthalia elongata and Cystoseira nodicaulis. Antioxidant activity and total phenolic content assays were used as an index for producing phlorotannin fractions, enriched using molecular weight cut-off dialysis with subsequent flash chromatography to profile phlorotannin isomers in these macroalgae. These fractions were profiled using UPLC-MS with multiple reaction monitoring (MRM and the level of isomerization for specific molecular weight phlorotannins between 3 and 16 monomers were determined. The majority of the low molecular weight (LMW phlorotannins were found to have a molecular weight range equivalent to 4–12 monomers of phloroglucinol. The level of isomerization within the individual macroalgal species differed, resulting in substantially different numbers of phlorotannin isomers for particular molecular weights. F. vesiculosus had the highest number of isomers of 61 at one specific molecular mass, corresponding to 12 phloroglucinol units (PGUs. These results highlight the complex nature of these extracts and emphasize the challenges involved in structural elucidation of these compounds.

  11. Molecular weight changes induced in an anionic polydimethylsiloxane by gamma irradiation in vacuum

    Satti, Angel J.; Andreucetti, Noemi A.; Ciolino, Andres E.; Vitale, Cristian; Sarmoria, Claudia; Valles, Enrique M.

    2010-01-01

    An anionic almost monodisperse linear polydimethylsiloxane (PDMS) was subjected to gamma irradiation under vacuum at room temperature. The molecular weight changes induced by the radiation process have been investigated using size exclusion chromatography (SEC) with refraction index (RI) and multi angle laser light scattering (MALLS) detectors, to obtain the number and weight average molecular weights of the irradiated samples. The analysis of the data indicates that crosslinking reactions predominated over scission reactions. The results obtained by an SEC-RI have confirmed the presence of small, but measurable amounts of scission. A previously developed mathematical model of the irradiation process that accounts for simultaneous scission and crosslinking and allows for both H- and Y-crosslinks, fitted well the measured molecular weight data. This prediction is in accordance with the experimental data obtained by 29 Si-Nuclear Magnetic Resonance spectroscopy (NMR) and previously reported data for commercial linear PDMS ().

  12. Studies on a microbially derived, high molecular weight inhibitor of plasma cholesteryl ester transfer protein

    Marschke, C.K.; McGee, J.E.; Melchior, G.W.; Castle, C.K.

    1989-01-01

    The authors have isolated an organism which accumulates an inhibitor of Cholesteryl Ester Transfer Protein (CETP). Purification of 100,000-fold was achieved by ammonium sulfate precipitation followed by Hydroxyl Apatite, Agarose AO.5, and Mono Q (Pharmacia) chromatographies. The use of 14 C-labelled protein molecular weight standards followed by SDS-PAGE revealed some proteolytic activity. However, inhibition of the proteases did not affect the inhibitor potency. The inhibitor has an estimated molecular weight of 40 Kd and appears to exist as two forms. One form was eluted from a Mono Q column by 100 mM NaCl while the other was not bound. Our evidence indicated that the bound form was progressively denatured, or proteolyzed, during storage of the fermentation beer, to the unbound form. Importantly though this molecular change did not affect either inhibitory activity or the apparent molecular weight

  13. Molecular weight determination of bisbenzyl-isoquinoline alkaloids by 252Cf-plasma desorption mass spectrometer

    Kohno, Hiroyuki; Tatsunami, Shinobu; Hiroi, Tomoko; Kouyama, Hiroshi; Taniguchi, Masashi; Yago, Nagasumi; Nakamura, Iwao

    1995-01-01

    Bisbenzylisoquinoline alkaloids of Stephania cepharantha have been used for various clinical purposes and recently reevaluated as stimulators of interleukin secretion in tissues. We analyzed molecular stuctures of bisbenzylisoquinoline alkaloids by determining their molecular weights using the 252 Cf-plasma desorption mass spectrometry (PDMS). The spectra were accumulated for 500 000 fission events. The acceleration voltage used here was 15 kV. Samples were analyzed using nitrocellulose-coated sample targets. Of the 5 alkaloids studied here, cepharanthine gave a main peak of molecular weight of 606.1 for the theoretical molecular weight of 606.7. The other minor peaks were considered to be demethylated fragment ions. 252 Cf-PDMS should be quite useful in studying structure, metabolism and pharmacokinetics of various drugs with extremely low coefficients of variation. (author)

  14. Elevated levels of high-molecular-weight adiponectin in type 1 diabetes

    Leth, H.; Andersen, K.K.; Frystyk, J.

    2008-01-01

    BACKGROUND: Several studies have shown that type 1 diabetic patients have elevated total levels of the adipocyte-derived adipocytokine adiponectin. However, adiponectin circulates in three different subforms, and the high-molecular-weight (HMW) subform is believed to be the primary biologically...... active form. The effects of the medium-molecular-weight (MMW) subform and the low-molecular-weight (LMW) subform are still unresolved. PURPOSE: The objective of the study was to investigate the distribution of the three molecular subforms of adiponectin in well-characterized groups of type 1 diabetics...... with varying degrees of nephropathy as well as in healthy control subjects. STUDY POPULATION: Two hundred seven individuals were included: 58 type 1 diabetics with normoalbuminuria, 46 with microalbuminuria, 46 with macroalbuminuria, and 57 matched controls. METHODS: The HMW, MMW, and LMW subforms were...

  15. Exercise increases human skeletal muscle insulin sensitivity via coordinated increases in microvascular perfusion and molecular signaling

    Sjøberg, Kim Anker; Frøsig, Christian; Kjøbsted, Rasmus

    2017-01-01

    and increased similarly in both legs during the clamp and L-NMMA had no effect on these insulin-stimulated signaling pathways. Therefore, acute exercise increases insulin sensitivity of muscle by a coordinated increase in insulin-stimulated microvascular perfusion and molecular signaling at the level of TBC1D4...... and glycogen synthase in muscle. This secures improved glucose delivery on the one hand and increased ability to take up and dispose of the delivered glucose on the other hand....

  16. Effects of increased vertebral number on carcass weight in PIC pigs.

    Huang, Jieping; Zhang, Mingming; Ye, Runqing; Ma, Yun; Lei, Chuzhao

    2017-12-01

    Variation of the vertebral number is associated with carcass traits in pigs. However, results from different populations do not match well with others, especially for carcass weight. Therefore, effects of increased vertebral number on carcass weight were investigated by analyzing the relationship between two loci multi-vertebra causal loci (NR6A1 g.748 C > T and VRTN g.20311_20312ins291) and carcass weight in PIC pigs. Results from the association study between vertebral number and carcass weight showed that increased thoracic number had negative effects on carcass weight, but the results were not statistically significant. Further, VRTN Ins/Ins genotype increased more than one thoracic than that of Wt/Wt genotype on average in this PIC population. Meanwhile, there was a significant negative effect of VRTN Ins on carcass weight (P carcass weight in PIC pigs. © 2017 Japanese Society of Animal Science.

  17. Yokukansankachimpihange increased body weight but not food-incentive motivation in wild-type mice.

    Hamaguchi, Takuya; Tsutsui-Kimura, Iku; F Tanaka, Kenji; Mimura, Masaru

    2017-08-01

    Yokukansankachimpihange (YKSCH), a traditional Japanese medicine, is widely used for the amelioration of the behavioral and psychological symptoms of dementia with digestive dysfunction. Regardless of its successful use for digestive dysfunction, the effect of YKSCH on body weight was unknown. Furthermore, if YKSCH increased body weight, it might increase motivation according to Kampo medicine theory. Therefore, we investigated whether YKSCH had the potential to increase body weight and enhance motivation in mice. To address this, C57BL/6J mice were used to evaluate the long-term effect of YKSCH on body weight and food-incentive motivation. As part of the evaluation, we optimized an operant test for use over the long-term. We found that feeding mice YKSCH-containing chow increased body weight, but did not increase their motivation to food reward. We propose that YKSCH may be a good treatment option for preventing decrease in body weight in patients with dementia.

  18. Sampling of high molecular weight hydrocarbons with adsorbent tubes

    Stroemberg, B.

    1996-12-01

    Adsorption tubes have been used to determine the content of hydrocarbons in gas samples from small scale combustion and gasification of biomass. Compounds from benzene (mw 78) to indeno (1,2,3-cd) pyrene (mw 276) have been examined. The results show that it is possible to analyze polyaromatic hydrocarbons (PAH) with 4 aromatic rings (mw 202). Detection limits for these compounds are 3 . PAH with higher molecule weight can be identified and quantified in samples with high amounts of PAH e.g. at gasification of biomass. Sampling on adsorption tubes is extremely quick and easy. The tube is inserted in the gas of interest and the sample is sucked through the tube with a pump. Sampling times of 2-10 minutes are often sufficient. High moisture content in the gas may result in losses of the most volatile compounds, when drying. Even very low concentrations of water in the tube may cause ice formation in the cold-trap and the sample will be destroyed. The analysis is unfortunately time-consuming because the desorption oven must be cooled between every analysis. This will reduce the number of samples which can be analyzed per day. The tubes can be stored for several weeks before analysis without deterioration. 4 refs, 5 figs, 3 tabs

  19. The polysaccharide and low molecular weight components of Opuntia ficus indica cladodes: Structure and skin repairing properties.

    Di Lorenzo, Flaviana; Silipo, Alba; Molinaro, Antonio; Parrilli, Michelangelo; Schiraldi, Chiara; D'Agostino, Antonella; Izzo, Elisabetta; Rizza, Luisa; Bonina, Andrea; Bonina, Francesco; Lanzetta, Rosa

    2017-02-10

    The Opuntia ficus-indica multiple properties are reflected in the increasing interest of chemists in the identification of its natural components having pharmaceutical and/or cosmetical applications. Here we report the structural elucidation of Opuntia ficus-indica mucilage that highlighted the presence of components differing for their chemical nature and the molecular weight distribution. The high molecular weight components were identified as a linear galactan polymer and a highly branched xyloarabinan. The low molecular weight components were identified as lactic acid, D-mannitol, piscidic, eucomic and 2-hydroxy-4-(4'-hydroxyphenyl)-butanoic acids. A wound healing assay was performed in order to test the cicatrizing properties of the various components, highlighting the ability of these latter to fasten dermal regeneration using a simplified in vitro cellular model based on a scratched keratinocytes monolayer. The results showed that the whole Opuntia mucilage and the low molecular weight components are active in the wound repair. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Low molecular weight squash trypsin inhibitors from Sechium edule seeds.

    Laure, Hélen J; Faça, Vítor M; Izumi, Clarice; Padovan, Júlio C; Greene, Lewis J

    2006-02-01

    Nine chromatographic components containing trypsin inhibitor activity were isolated from Sechium edule seeds by acetone fractionation, gel filtration, affinity chromatography and RP-HPLC in an overall yield of 46% of activity and 0.05% of protein. The components obtained with highest yield of total activity and highest specific activity were sequenced by Edman degradation and their molecular masses determined by mass spectrometry. The inhibitors contained 31, 32 and 27 residues per molecule and their sequences were: SETI-IIa, EDRKCPKILMRCKRDSDCLAKCTCQESGYCG; SETI-IIb, EEDRKCPKILMRCKRDSDCLAKCTCQESGYCG and SETI-V, CPRILMKCKLDTDCFPTCTCRPSGFCG. SETI-IIa and SETI-IIb, which differed by an amino-terminal E in the IIb form, were not separable under the conditions employed. The sequences are consistent with consensus sequences obtained from 37 other inhibitors: CPriI1meCk_DSDCla_C_C_G_CG, where capital letters are invariant amino acid residues and lower case letters are the most preserved in this position. SETI-II and SETI-V form complexes with trypsin with a 1:1 stoichiometry and have dissociation constants of 5.4x10(-11)M and 1.1x10(-9)M, respectively.

  1. Radiation polymerization of acrylamide with super-high molecular weight in inverse emulsion

    Ye Qiang; Ge Xuewu; Xu Xiangling; Zhang Zhicheng

    1998-01-01

    The inverse emulsion polymerization of acrylamide has been studied with γ-ray initiation. Polyacrylamide with super high molecular weight over ten million (11 x 10 6 ), which is very important in application as flocculant, is obtained. In this work, some methods are taken to enhance the molecular weight as follows: (1) In order to prepare soluble polyacrylamide with super high molecular weight, the better conditions are: the emulsifier content is about 2% and the monomer concentration is about 20%∼24% in the composition of monomer emulsion, and the absorbed dose is about 500∼600 Gy. (2) Initiating with high dose rate and polymerizing with low dose rate can not only enhance the molecular weight of product, but also curtail the polymerizing time. (3) Stopping radiation when the conversion gets to about 10% and post-polymerizing outside the radiation source until the conversion gets to 82% can obtain polyacrylamide with super high molecular weight, and shorten the irradiation time as well

  2. Antioxidation activities of low-molecular-weight gelatin hydrolysate isolated from the sea cucumber Stichopus japonicus

    Wang, Jingfeng; Wang, Yuming; Tang, Qingjuan; Wang, Yi; Chang, Yaoguang; Zhao, Qin; Xue, Changhu

    2010-03-01

    Gelatin extracted from the body wall of the sea cucumber ( Stichopus japonicus) was hydrolyzed with flavourzyme. Low-molecular-weight gelatin hydrolysate (LMW-GH) of 700-1700 Da was produced using an ultrafiltration membrane bioreactor system. Chemiluminescence analysis revealed that LMW-GH scavenges high free radicals in a concentration-dependent manner; IC50 value for superoxide and hydroxyl radicals was 442 and 285 μg mL-1, respectively. LMW-GH exhibited excellent inhibitory characteristics against melanin synthesis and tyrosinase activity in B16 cells. Furthermore, LMW-GH notably increased intracellular glutathione (GSH), which in turn suppressed melanogenesis. LMW-GH performs antioxidation activity, holding the potential of being used as a valuable ingredient in function foods, cosmetics and pharmaceuticals or nutriceuticals.

  3. Calcium binding to low molecular weight compounds and health promoting products

    Vavrusova, Martina

    absorption. Therefore, calcium as an essential nutrient should not be underestimated in our diet. Milk and dairy products are good sources of bioavailable calcium due to specific protein binding. Other sources of calcium, apart from a balanced and healthy diet, are calcium supplements and calcium fortified...... food. Therefore, an understanding of the basic chemistry of calcium binding to low molecular weight compounds can contribute to a general knowledge about calcium bioavailability and also to product improvement. Calcium precipitation with palmitate was described by a first-order reaction for conditions...... of excess calcium in neutral aqueous solutions with a stoichiometry Ca:Pal lower than 1:2. Increasing pH during aging of the precipitate and solubility product determination lead to a suggestion of an initial precipitation of calcium hydroxy palmitate as a possible precursor phase. The binding of calcium...

  4. Surface engineering on mesoporous silica chips for enriching low molecular weight phosphorylated proteins

    Hu, Ye; Peng, Yang; Lin, Kevin; Shen, Haifa; Brousseau, Louis C., III; Sakamoto, Jason; Sun, Tong; Ferrari, Mauro

    2011-02-01

    Phosphorylated peptides and proteins play an important role in normal cellular activities, e.g., gene expression, mitosis, differentiation, proliferation, and apoptosis, as well as tumor initiation, progression and metastasis. However, technical hurdles hinder the use of common fractionation methods to capture phosphopeptides from complex biological fluids such as human sera. Herein, we present the development of a dual strategy material that offers enhanced capture of low molecular weight phosphoproteins: mesoporous silica thin films with precisely engineered pore sizes that sterically select for molecular size combined with chemically selective surface modifications (i.e. Ga3+, Ti4+ and Zr4+) that target phosphoroproteins. These materials provide high reproducibility (CV = 18%) and increase the stability of the captured proteins by excluding degrading enzymes, such as trypsin. The chemical and physical properties of the composite mesoporous thin films were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy and ellipsometry. Using mass spectroscopy and biostatistics analysis, the enrichment efficiency of different metal ions immobilized on mesoporous silica chips was investigated. The novel technology reported provides a platform capable of efficiently profiling the serum proteome for biomarker discovery, forensic sampling, and routine diagnostic applications.Phosphorylated peptides and proteins play an important role in normal cellular activities, e.g., gene expression, mitosis, differentiation, proliferation, and apoptosis, as well as tumor initiation, progression and metastasis. However, technical hurdles hinder the use of common fractionation methods to capture phosphopeptides from complex biological fluids such as human sera. Herein, we present the development of a dual strategy material that offers enhanced capture of low molecular weight phosphoproteins: mesoporous

  5. Can thiolation render a low molecular weight polymer of just 20-kDa mucoadhesive?

    Mahmood, Arshad; Bonengel, Sonja; Laffleur, Flavia; Ijaz, Muhammad; Idrees, Muneeb Ahmad; Hussain, Shah; Huck, Christian W; Matuszczak, Barbara; Bernkop-Schnürch, Andreas

    2016-01-01

    The objective was to investigate whether even low-molecular weight polymers (LMWPs) can be rendered mucoadhesive due to thiolation. Interceded by the double catalytic system carbodiimide/N-hydroxysuccinimide, cysteamine was covalently attached to a copolymer, poly(4-styrenesulfonic acid-co-maleic acid) (PSSA-MA) exhibiting a molecular weight of just 20 kDa. Depending on the amount of added N-hydroxysuccinimide and cysteamine, the resulting PSSA-MA-cysteamine (PC) conjugates exhibited increasing degree of thiolation, highest being "PC 2300" exhibiting 2300.16 ± 149.86 μmol thiol groups per gram of polymer (mean ± SD; n = 3). This newly developed thiolated polymer was evaluated regarding mucoadhesive, rheological and drug release properties as well from the toxicological point of view. Swelling behavior in 100 mM phosphate buffer pH 6.8 was improved up to 180-fold. Furthermore, due to thiolation, the mucoadhesive properties of the polymer were 240-fold improved. Rheological measurements of polymer/mucus mixtures confirmed results obtained by mucoadhesion studies. In comparison to unmodified polymer, PC 2300 showed 2.3-, 2.3- and 2.4-fold increase in dynamic viscosity, elastic modulus and viscous modulus, respectively. Sustained release of the model drug codeine HCl out of the thiomer was provided for 2.5 h (p polymer. Moreover, the thiomer was found non-toxic over Caco-2 cells for a period of 6- and 24-h exposure. Findings of the present study provide evidence that due to thiolation LMWPs can be rendered highly mucoadhesive as well as cohesive and that a controlled drug release out of such polymers can be provided.

  6. Impact of Low Molecular Weight Poly(3-hexylthiophene)s as Additives in Organic Photovoltaic Devices.

    Seibers, Zach D; Le, Thinh P; Lee, Youngmin; Gomez, Enrique D; Kilbey, S Michael

    2018-01-24

    Despite tremendous progress in using additives to enhance the power conversion efficiency of organic photovoltaic devices, significant challenges remain in controlling the microstructure of the active layer, such as at internal donor-acceptor interfaces. Here, we demonstrate that the addition of low molecular weight poly(3-hexylthiophene)s (low-MW P3HT) to the P3HT/fullerene active layer increases device performance up to 36% over an unmodified control device. Low MW P3HT chains ranging in size from 1.6 to 8.0 kg/mol are blended with 77.5 kg/mol P3HT chains and [6,6]-phenyl C 61 butyric acid methyl ester (PCBM) fullerenes while keeping P3HT/PCBM ratio constant. Optimal photovoltaic device performance increases are obtained for each additive when incorporated into the bulk heterojunction blend at loading levels that are dependent upon additive MW. Small-angle X-ray scattering and energy-filtered transmission electron microscopy imaging reveal that domain sizes are approximately invariant at low loading levels of the low-MW P3HT additive, and wide-angle X-ray scattering suggests that P3HT crystallinity is unaffected by these additives. These results suggest that oligomeric P3HTs compatibilize donor-acceptor interfaces at low loading levels but coarsen domain structures at higher loading levels and they are consistent with recent simulations results. Although results are specific to the P3HT/PCBM system, the notion that low molecular weight additives can enhance photovoltaic device performance generally provides a new opportunity for improving device performance and operating lifetimes.

  7. Increased Flap Weight and Decreased Perforator Number Predict Fat Necrosis in DIEP Breast Reconstruction

    Carolyn L. Mulvey, BS

    2013-05-01

    Conclusions: Flaps with increasing weight have increased risk of fat necrosis. These data suggest that inclusion of more than 1 perforator may decrease odds of fat necrosis in large flaps. Perforator flap breast reconstruction can be performed safely; however, considerations concerning race, body mass index, staging with tissue expanders, perforator number, and flap weight may optimize outcomes.

  8. Fatigue evaluation of the increased weight limit on transit railway bridges.

    2014-09-01

    The recent increase of freight railcar weight limits from 263,000 lbs. to 286,000 lbs. raises concerns for the safety of bridges : on transit passenger rail systems, since they were not designed for this weight increase. Thus, there is a need to asse...

  9. Tests of potential functional barriers for laminated multilayer food packages. Part II: Medium molecular weight permeants.

    Simal-Gándara, J; Sarria-Vidal, M; Rijk, R

    2000-09-01

    Experiments were performed to characterize the kinetics of the permeation of different medium molecular weight model permeants: bisphenol A, warfarin and anthracene, from liquid paraffin, through a surrogate potential functional barrier (25 microns-thick orientated polypropylene--OPP) into the food simulants olive oil and 3% (w/v) acetic acid. The characterization of permeation kinetics generally observed the permeation models previously reported to explain the experimental permeation results obtained for a low molecular weight group of model permeants. In general, the model permeants exhibited behaviour consistent with their relative molecular weights with respect to (a) the time taken to attain steady-state permeation into the food simulant in which they were more soluble, (b) their subsequent steady-state permeation rates, and (c) their partition between liquid paraffin and the OPP membrane.

  10. Characteristics and bioactivities of different molecular weight polysaccharides from camellia seed cake.

    Xu, Zhou; Li, Xu; Feng, Shiling; Liu, Jing; Zhou, Lijun; Yuan, Ming; Ding, Chunbang

    2016-10-01

    Four polysaccharides, namely COP-1, COP-2, COP-3 and COP-4, were ultrafiltrated from crud Camellia oleifera seed cake polysaccharides (COP-c), purified, and characterized, including the determination of antioxidant and antiproliferative activities. Their molecular weights were 7.9, 36, 83 and 225kDa, respectively. All COPs showed the similar FT-IR spectrums, but significant differentials in monosaccharide components. COP-2 exhibited the highest radical scavenging abilities. COP-1 has the strongest metal chelating capabilities. Although with higher molecular weight, COP-4 showed the poorest antioxidant abilities. These results suggested appreciate molecular weight COP possessed a better antioxidant activities. Additionally, all COPs had non-significant antiproliferative abilities in HaLa and HepG2 cells. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Loss of high-molecular-weight cytokeratin antigenicity in prostate tissue obtained by transurethral resections

    Multhaupt, H A; Fessler, J N; Warhol, M J

    2000-01-01

    could be restored in these specimens by antigen retrieval in a low pH citrate buffer using a microwave heat technique. Keratin staining in needle biopsies and total prostatectomies was unaffected. CONCLUSION: In summary, our results indicate the technique of transurethral resection results in a specific......OBJECTIVE: Staining of prostatic basal cells for the expression of high-molecular-weight cytokeratin has been suggested as a way of distinguishing benign from malignant prostate glands. We evaluated the utility of high-molecular-weight cytokeratin in the diagnosis of malignancy in prostate...... specimens obtained in various ways. DESIGN: Prostate tissues obtained from needle biopsies, transurethral resections, and total prostatectomies were immunostained with monoclonal antibody 34betaE12, an antibody directed against high-molecular-weight cytokeratins. RESULTS: Antiserum to high...

  12. Acrylate oligomers in ultraviolet cured PSA's glass transition, molecular weight versus peel strength

    Miller, H.C.

    1999-01-01

    Typically those not skilled in the art relate Glass Transition Temperature to Pressure Sensitive Adhesives. You need a low Tg material to prepare good pressure sensitive adhesives. This report deals with a wide range acrylate terminated oligomers in a standard formulation. Molecular weight, chemical structure variations are examined versus the Glass Transition of the oligomers and final peel strength. Each formulated adhesive will require unique oligomer properties to reach one hundred newtons per 100 millimeters (5.71 pounds per square inch) peel strength. Excellent peel strengths may be obtained with oligomer molecular weight ranging from six thousand to one thousand molecular weight and glass transition temperatures ranging from minus seventy four degrees centigrade up to thirteen degrees centigrade

  13. Molecular weights distribution and temperature effects in the styrene polymerization initiated with gamma rays

    Burillo, G.; Martinez, R.

    1979-01-01

    The polymerization of styrene irradiated in a 60 CO source to 18 0 C temperature and to 70 0 C temperature was studied, in order to reduce the irradiation time raising the polymerization rate and looking for a highest molecular weight. The radiation doses used were from 0.2 to 33.26 Mrad, at the rate of 56 rad/sec, the percent of polymerization and the molecular weight formed were determined, the results indicate one highest molecular weight of 132,700 when the radiation dose of 20 Mrad and the temperature of 20 0 C were used, and one of 395,000 when the irradiation is carried out to 70 0 C. (author)

  14. Low molecular weight compounds as effective dispersing agents in the formation of colloidal silver nanoparticles

    Natsuki, Jun; Natsuki, Toshiaki, E-mail: natsuki@shinshu-u.ac.jp; Abe, Takao [Shinshu University, Faculty of Textile Science and Technology (Japan)

    2013-03-15

    A convenient method to synthesize uniform, well-dispersed colloidal silver nanoparticles is described. Aldonic acid or {alpha}-hydroxy acid compounds of low molecular weight are used instead of polymeric compounds as dispersing agents to prepare silver nanoparticles. The size, conformation, and electrical conductivity of the silver nanoparticles, and the effect and function of the dispersing agents are investigated in detail. Using these low molecular weight compounds as dispersing agents, silver nanoparticles with a diameter of 10 nm or less and high electrical conductivity can be obtained. In addition, this procedure allows silver nanoparticles to be sintered at 150 Degree-Sign C, which is lower than that required for silver nanoparticle formulation using polymeric compounds (200 Degree-Sign C). The silver nanoparticles produced by this process can be used to prepare various inks and to manufacture electronic circuits. It is found that low molecular weight compounds are more effective dispersing agents than polymeric compounds in the formation of silver nanoparticles.

  15. Calibration of low molecular weight polypeptides by sodium dodecylsulphate polyacrylamide gel electrophoresis

    Glyn, M.C.P.; Bull, J.; Wright, R.

    1982-01-01

    Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) is a technique commonly used in determining molecular weights of large proteins and peptides. This technique is used to analyse viral peptides, available in amounts too small to be monitored by an ultraviolet spectrophotometer. An experiment is described (with the limiting factor to use the SDS-PAGE technique), to determine the molecular weight peptides and the results are given to fit the linear relationship log M=4.286 - 0.42 V(e)/V(o). The results given by the SDS-PAGE system, described in the article, show that the experimental values describe a linear relationship with good resolution of low molecular weight peptides in the range 3 000 to 14 000 and that a partial cyanogen bromide digest of cytochrome c is suitable for calibration standards

  16. A weight-loss program adapted to the menstrual cycle increases weight loss in healthy, overweight, premenopausal women

    Geiker, Nina R W; Ritz, Christian; Pedersen, Sue D

    2016-01-01

    compared with the effect of simple energy restriction. DESIGN: A total of 60 healthy, overweight, premenopausal women were included in a 6-mo weight-loss program in which each subject consumed a diet of 1600 kcal/d. Subjects were randomly assigned to either a combined diet and exercise program...... that was tailored to metabolic changes of the menstrual cycle (Menstralean) or to undergo simple energy restriction (control). RESULTS: Thirty-one women (19 Menstralean and 12 control women) completed the study [mean ± SD body mass index (in kg/m(2)): 32.0 ± 5.2]. Both groups lost weight during the study....... CONCLUSION: A differentiated diet and exercise program that is tailored to counteract food cravings and metabolic changes throughout the menstrual cycle may increase weight loss above that achieved with a traditional diet and exercise program in women who can comply with the program. This trial...

  17. Molecular weight-dependent degradation and drug release of surface-eroding poly(ethylene carbonate).

    Bohr, Adam; Wang, Yingya; Harmankaya, Necati; Water, Jorrit J; Baldursdottír, Stefania; Almdal, Kristoffer; Beck-Broichsitter, Moritz

    2017-06-01

    Poly(ethylene carbonate) (PEC) is a unique biomaterial showing significant potential for controlled drug delivery applications. The current study investigated the impact of the molecular weight on the biological performance of drug-loaded PEC films. Following the preparation and thorough physicochemical characterization of diverse PEC (molecular weights: 85, 110, 133, 174 and 196kDa), the degradation and drug release behavior of rifampicin- and bovine serum albumin-loaded PEC films was investigated in vitro (in the presence and absence of cholesterol esterase), in cell culture (RAW264.7 macrophages) and in vivo (subcutaneous implantation in rats). All investigated samples degraded by means of surface erosion (mass loss, but constant molecular weight), which was accompanied by a predictable, erosion-controlled drug release pattern. Accordingly, the obtained in vitro degradation half-lives correlated well with the observed in vitro half-times of drug delivery (R 2 =0.96). Here, the PEC of the highest molecular weight resulted in the fastest degradation/drug release. When incubated with macrophages or implanted in animals, the degradation rate of PEC films superimposed the results of in vitro incubations with cholesterol esterase. Interestingly, SEM analysis indicated a distinct surface erosion process for enzyme-, macrophage- and in vivo-treated polymer films in a molecular weight-dependent manner. Overall, the molecular weight of surface-eroding PEC was identified as an essential parameter to control the spatial and temporal on-demand degradation and drug release from the employed delivery system. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Surface properties of poly(acrylonitrile) (PAN) precipitation polymerized in supercritical CO2 and the influence of the molecular weight.

    Shen, Qing; Gu, Qing-Feng; Hu, Jian-Feng; Teng, Xin-Rong; Zhu, Yun-Feng

    2003-11-15

    In this paper, the surface properties, e.g., the total surface free energy and the related Lifshitz-van der Waals and Lewis acid-base components, of polyacrylonitrile (PAN) precipitation polymerized in supercritical CO(2) have been characterized. Moreover, the influence of molecular weight varying has been also investigated. Results show that the surface properties of PAN resulting from supercritical CO(2) are different from those obtained by the conventional method. Of these data, one important finding is that the supercritical CO(2) PAN seems to decrease the surface free energy with the increased molecular weight. Based on previous recorded NMR spectra of this PAN and especially compared to commercial PAN, such phenomena are discussed and ascribed to an increase of the H-bonds and a reduction of the isotacticity in the supercritical CO(2) condition for PAN.

  19. High molecular weight poly(L-lactide) and poly(ethylene oxide) blends : Thermal characterization and physical properties

    Nijenhuis, AJ; Colstee, E; Grijpma, DW; Pennings, AJ

    1996-01-01

    The miscibility of high molecular weight poly(L-lactide) (PLLA) with high molecular weight poly(ethylene oxide) (PEG) was studied by differential scanning calorimetry. Ail blends containing up to 50 weight% PEO showed single glass transition temperatures. The PLLA and PEO melting temperatures were

  20. Molecular weight-dependent degradation and drug release of surface-eroding poly(ethylene carbonate)

    Bohr, Adam; Wang, Yingya; Harmankaya, Necati

    2017-01-01

    .7 macrophages) and in vivo (subcutaneous implantation in rats). All investigated samples degraded by means of surface erosion (mass loss, but constant molecular weight), which was accompanied by a predictable, erosion-controlled drug release pattern. Accordingly, the obtained in vitro degradation half......Poly(ethylene carbonate) (PEC) is a unique biomaterial showing significant potential for controlled drug delivery applications. The current study investigated the impact of the molecular weight on the biological performance of drug-loaded PEC films. Following the preparation and thorough...... to control the spatial and temporal on-demand degradation and drug release from the employed delivery system....

  1. Effect of molecular weight on the vibronic structure of a diketopyrrolopyrrole polymer

    Hayes, Sophia C.

    2016-09-27

    Resonance Raman Spectroscopy (RRS) is employed in this study to examine the influence of molecular weight on the optical response of a diketopyrrolopyrrole polymer (DPP-TT-T) in solution. The vibronic structure observed for the ground state absorption of this polymer is found to vary with molecular weight and solvent. Resonance Raman Intensity Analysis (RRIA) revealed that the absorption spectra can be described by at least two dipole-allowed transitions and the vibronic structure variation is due to differing contributions from linear and curved segments of the polymer.

  2. Effect of molecular weight on the vibronic structure of a diketopyrrolopyrrole polymer

    Hayes, Sophia C.; Pieridou, Galatia; Vezie, Michelle; Few, Sheridan; Bronstein, Hugo; Meager, Iain; McCulloch, Iain; Nelson, Jenny

    2016-01-01

    Resonance Raman Spectroscopy (RRS) is employed in this study to examine the influence of molecular weight on the optical response of a diketopyrrolopyrrole polymer (DPP-TT-T) in solution. The vibronic structure observed for the ground state absorption of this polymer is found to vary with molecular weight and solvent. Resonance Raman Intensity Analysis (RRIA) revealed that the absorption spectra can be described by at least two dipole-allowed transitions and the vibronic structure variation is due to differing contributions from linear and curved segments of the polymer.

  3. Correlation between the estimated molecular weight and the immunological properties of 125I-TSH

    Quiroga, S.E.; Ciscato, V.A.; Barmasch, M.; Kurcbart, H.; Veira de Giacomini, S.; Altschuler, N.; Caro, R.A.

    1976-09-01

    Thyrotropic Stimulating Hormone (TSH) was radioiodinated by the Chloramine T method in order to be used in radioimmu-noassay procedures. It was purified by gel filtration and each fraction of the eluate was analyzed in order to determine which one had the most suitable behaviour for that use. The molecular weight of each fraction was estimated, as well as its immunological reactivity and its non-specific binding. The 125 I-TSH fraction with better properties was the closest to the molecular weight of the native hormone, which is found at the posterior shoulder of the main proteic peak of the elution pattern. (author) [es

  4. Photocuring of stimulus responsive membranes for controlled-release of drugs having different molecular weights

    Ng, Loo-Teck; Nakayama, Hiroshi; Kaetsu, Isao; Uchida, Kumao

    2005-01-01

    Intelligent drug delivery membranes were prepared by photocuring poly(acrylic acid) coatings onto poly(2-hydroxyethyl methacrylate) membranes each with model drugs of different molecular weights being incorporated. pH-responsive release behaviours of the model drugs which included sodium salicylate, nicotinamide, nicotinic acid, methylene blue, brilliant green and crystal violet were investigated. Only the membrane with methylene blue incorporated showed a clear pH-responsive release and other drug-incorporated membranes showed no intelligent behaviour. These phenomena were explained in terms of the difference in diffusivity of drugs through polymer matrices of the membranes attributable to the difference in the molecular weights of drugs

  5. Photocuring of stimulus responsive membranes for controlled-release of drugs having different molecular weights

    Ng, Loo-Teck [School of Science, Food and Horticulture, University of Western Sydney, Locked bag 1797, Penrith South DC, NSW 1797 (Australia)]. E-mail: l.ng@uws.edu.au; Nakayama, Hiroshi [Department of Nuclear Engineering, Faculty of Science and technology, Kinki University, Kowakae, 3-4-1, Higashi-Osaka 577-8502 (Japan); Kaetsu, Isao [Department of Nuclear Engineering, Faculty of Science and technology, Kinki University, Kowakae, 3-4-1, Higashi-Osaka 577-8502 (Japan)]. E-mail: kaetsu@ned.kindai.ac.jp; Uchida, Kumao [Department of Nuclear Engineering, Faculty of Science and technology, Kinki University, Kowakae, 3-4-1, Higashi-Osaka 577-8502 (Japan)

    2005-06-01

    Intelligent drug delivery membranes were prepared by photocuring poly(acrylic acid) coatings onto poly(2-hydroxyethyl methacrylate) membranes each with model drugs of different molecular weights being incorporated. pH-responsive release behaviours of the model drugs which included sodium salicylate, nicotinamide, nicotinic acid, methylene blue, brilliant green and crystal violet were investigated. Only the membrane with methylene blue incorporated showed a clear pH-responsive release and other drug-incorporated membranes showed no intelligent behaviour. These phenomena were explained in terms of the difference in diffusivity of drugs through polymer matrices of the membranes attributable to the difference in the molecular weights of drugs.

  6. Structure and allosteric effects of low-molecular-weight activators on the protein kinase PDK1

    Hindie, Valerie; Stroba, Adriana; Zhang, Hua

    2009-01-01

    -dependent activation of AGC kinases. The AGC kinase PDK1 is activated by the docking of a phosphorylated motif from substrates. Here we present the crystallography of PDK1 bound to a rationally developed low-molecular-weight activator and describe the conformational changes induced by small compounds in the crystal...... molecular details of the allosteric changes induced by small compounds that trigger the activation of PDK1 through mimicry of phosphorylation-dependent conformational changes....

  7. Effect of molecular weight and testing rate on adhesion property of pressure-sensitive adhesives prepared from epoxidized natural rubber

    Khan, Imran; Poh, B.T.

    2011-01-01

    Research highlights: → Elucidation of adhesion property of epoxidized natural rubber (ENR 25). → Correlation of peel and shear strength with molecular weight and rate of testing. → Confirmation of miscibility of tackifier and ENR 25 by DSC and FTIR study. → Applicability of Fox equation in ENR 25/coumarone-indene resin system. -- Abstract: The dependence of peel strength and shear strength of epoxidized natural rubber (ENR 25)-based pressure-sensitive adhesive on molecular weight and rate of testing was investigated using coumarone-indene as the tackifying resin. Toluene and polyethylene terephthalate (PET) were used as the solvent and substrate respectively throughout the study. A SHEEN hand coater was used to coat the adhesive on the substrate at a coating thickness of 120 μm. All the adhesion properties were determined by a Llyod Adhesion Tester operating at different rates of testing. Result shows that peel strength and shear strength increases up to an optimum molecular weight of 6.5 x 10 4 of ENR 25. For peel strength, the observation is attributed to the combined effects of wettability and mechanical strength of rubber at the optimum molecular weight, whereas for the shear strength, it is ascribed to the increasing amount of adhesive present in the coating layer which enhances the shear resistance of the adhesive. Peel strength and shear strength also increases with increase in rate of testing, an observation which is associated to the viscoeslastic response of the adhesive. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) study confirms the miscibility of tackifier and the ENR 25.

  8. Stripping of 1.04 MeV per nucleon krypton ions in high molecular weight vapours

    Eastham, D.A.; Joy, T.; Clark, R.B.; King, R.

    1976-01-01

    Equilibrium charge state distributions have been measured for 1.04 MeV per nucleon krypton ions in heavy vapours with molecular weights from 462 to 6500. Non-equilibrium data are presented for the heaviest vapour. A maximum increase of 0.8 in the mean charge is found relative to a conventional diatomic gas but the pressures required are two orders of magnitude less. (Auth.)

  9. Effects of low molecular weight organic acids on 137Cs release from contaminated soils

    Chiang, Po Neng; Wang, Ming Kuang; Huang, Pan Ming; Wang, Jeng Jong

    2011-01-01

    Radio pollutant removal is one of several priority restoration strategies for the environment. This study assessed the effect of low molecular weight organic acid on the lability and mechanisms for release of 137 Cs from contaminated soils. The amount of 137 Cs radioactivity released from contaminated soils reacting with 0.02 M low molecular weight organic acids (LMWOAs) specifically acetic, succinic, oxalic, tartaric, and citric acid over 48 h were 265, 370, 760, 850, and 1002 Bq kg -1 , respectively. The kinetic results indicate that 137 Cs exhibits a two-step parabolic diffusion equation and a good linear relationship, indicating that the parabolic diffusion equation describes the data quite well, as shown by low p and high r 2 values. The fast stage, which was found to occur within a short period of time (0.083-3 h), corresponds to the interaction of LMWOAs with the surface of clay minerals; meanwhile, during the slow stage, which occurs over a much longer time period (3-24 h), desorption primarily is attributed to inter-particle or intra-particle diffusion. After a fifth renewal of the LMWOAs, the total levels of 137 Cs radioactivity released by acetic, succinic, oxalic, tartaric, and citric acid were equivalent to 390, 520, 3949, 2061, and 4422 Bq kg -1 soil, respectively. H + can protonate the hydroxyl groups and oxygen atoms at the broken edges or surfaces of the minerals, thereby weakening Fe-O and Al-O bonds. After protonation of H + , organic ligands can attack the OH and OH 2 groups in the minerals easily, to form complexes with surface structure cations, such as Al and Fe. The amounts of 137 Cs released from contaminated soil treated with LMWOAs were substantially increased, indicating that the LMWOAs excreted by the roots of plants play a critical role in 137 Cs release.

  10. Effect of poly(lactide-co-glycolide) molecular weight on the release of dexamethasone sodium phosphate from microparticles.

    Jaraswekin, Saowanee; Prakongpan, Sompol; Bodmeier, Roland

    2007-03-01

    The objective of this study was to investigate the effect of poly(lactide-co-glycolide) (PLGA) molecular weight (Resomer RG 502H, RG 503H, and RG 504H) on the release behavior of dexamethasone sodium phosphate-loaded microparticles. The microparticles were prepared by three modifications of the solvent evaporation method (O/W-cosolvent, O/W-dispersion, and W/O/W-methods). The encapsulation efficiency of microparticles prepared by the cosolvent- and W/O/W-methods increased from approximately 50% to >90% upon addition of NaCl to the external aqueous phase, while the dispersion method resulted in lower encapsulation efficiencies. The release of dexamethasone sodium phosphate from PLGA microparticles (>50 microm) was biphasic. The initial burst release correlated well with the porosity of the microparticles, both of which increased with increasing polymer molecular weight (RG 504H > 503H > 502H). The burst was also dependent on the method of preparation and was in the order of dispersion method > WOW method > consolvent method. In contrast to the higher molecular weight PLGA microparticles, the release from RG 502H microparticles prepared by cosolvent method was not affected by volume of organic solvent (1.5-3.0 ml) and drug loading (4-13%). An initial burst of approximately 10% followed by a 5-week sustained release phase was obtained. Microparticles with a size <50 microm released in a triphasic manner; an initial burst was followed by a slow release phase and then by a second burst.

  11. Pulsed NMR studies of crosslinking and entanglements in high molecular weight linear polydimethylsiloxanes

    Folland, R.; Charlesby, A.

    1977-01-01

    Pulsed NMR studies of proton spin relaxation are used to investigate both radiation-induced cross linking and entanglements in three high molecular weight linear polydimethylsiloxanes (Msub(w) = 26,000, 63,000 and 110,000). Particular emphasis is placed on the spin-spin relaxation since this is determined by the slower relative translational motions of the polymer chains and hence profoundly affected by the presence of intermolecular couplings such as crosslinks or entanglements. The spin-lattice relaxation times, T 1 , are determined by the fast anisotropic chain rotations and are rather insensitive to such intermolecular couplings. The spin-spin relaxation in these materials is represented by a double exponential decay involving two time constants, Tsub(2S) and Tsub(2L). The shorter component, Tsub(2S), is attributed to network material, which may be either of a dynamic form arising from temporary entanglements or of a permanent nature due to crosslinks. The concentration of entanglements depends on the initial molecular weight of the sample whereas the concentration of crosslinks is a function of the radiation dose. The longer component, Tsub(2L), is attributed to the non-network molecules. On the time scale of the NMR measurements the entanglements are shown to act in the same way as crosslinks. The variation of the relative proportions of network and non-network material with dose is shown to be accounted for by using standard gelation theory when allowance is made for the initial effective crosslink density due to entanglements. The analysis provides a value for the average molecular weight per entanglement point of 27,000 +- 1000 which is consistent with the critical molecular weight for entanglements of 29,000. The dependences of Tsub(2S) and Tsub(2L) on dose and molecular weight are also discussed in terms of the molecular motion. (author)

  12. Effect of molecular weight and concentration of hyaluronan on cell proliferation and osteogenic differentiation in vitro

    Zhao, Ningbo, E-mail: curl-zhao@163.com; Wang, Xin, E-mail: 394041230@qq.com; Qin, Lei, E-mail: qinlei30@126.com; Guo, Zhengze, E-mail: zhzeguo@163.com; Li, Dehua, E-mail: lidehuafmmu@163.com

    2015-09-25

    Hyaluronan (HA), the simplest glycosaminoglycan and a major component of the extracellular matrix, exists in various tissues. It is involved in some critical biological procedures, including cellular signaling, cell adhesion and proliferation, and cell differentiation. The effect of molecular weight (MW) and concentration of HA on cell proliferation and differentiation was controversial. In this study, we investigated the effect of MW and concentration of HA on the proliferation and osteogenic differentiation of rabbit bone marrow-derived stem cells in vitro. Results showed that high MW HA decreased the cell adhesion rate in a concentration-dependant manner. The cell adhesion rate was decreased by increasing MW of HA. Cell proliferation was significantly enhanced by low MW HA (P < 0.05). The factorial analysis indicated that MW and concentration had an interactive effect on the cell adhesion rate and cell proliferation (P < 0.05). High MW HA increased the mRNA expressions of ALP, RUNX-2 and OCN. The higher the MW was, the higher the mRNA expressions were. The factorial analysis indicated that MW and concentration had an interactive effect on ALP mRNA expression (P < 0.05). HA of higher MW and higher concentration promoted bone formation. These findings provide some useful information in understanding the mechanism underlying the effect of MW and concentration of HA on cell proliferation and differentiation. - Highlights: • Effect of hyaluronan on cell proliferation and differentiation is evaluated in vitro. • Hyaluronan of low molecular weight increases cell proliferation. • Hyaluronan of high molecular weight promotes cell osteogenic differentiation. • Molecular weight and concentration of hyaluronan show interactive effect.

  13. Mechanistic investigation of Fe(III) oxide reduction by low molecular weight organic sulfur species

    Eitel, Eryn M.; Taillefert, Martial

    2017-10-01

    Low molecular weight organic sulfur species, often referred to as thiols, are known to be ubiquitous in aquatic environments and represent important chemical reductants of Fe(III) oxides. Thiols are excellent electron shuttles used during dissimilatory iron reduction, and in this capacity could indirectly affect the redox state of sediments, release adsorbed contaminants via reductive dissolution, and influence the carbon cycle through alteration of bacterial respiration processes. Interestingly, the reduction of Fe(III) oxides by thiols has not been previously investigated in environmentally relevant conditions, likely due to analytical limitations associated with the detection of thiols and their oxidized products. In this study, a novel electrochemical method was developed to simultaneously determine thiol/disulfide pair concentrations in situ during the reduction of ferrihydrite in batch reactors. First order rate laws with respect to initial thiol concentration were confirmed for Fe(III) oxyhydroxide reduction by four common thiols: cysteine, homocysteine, cysteamine, and glutathione. Zero order was determined for both Fe(III) oxyhydroxide and proton concentration at circumneutral pH. A kinetic model detailing the molecular mechanism of the reaction was optimized with proposed intermediate surface structures. Although metal oxide overall reduction rate constants were inversely proportional to the complexity of the thiol structure, the extent of metal reduction increased with structure complexity, indicating that surface complexes play a significant role in the ability of these thiols to reduce iron. Taken together, these results demonstrate the importance of considering the molecular reaction mechanism at the iron oxide surface when investigating the potential for thiols to act as electron shuttles during dissimilatory iron reduction in natural environments.

  14. The Effect of an Increased Minimum Wage on Infant Mortality and Birth Weight.

    Komro, Kelli A; Livingston, Melvin D; Markowitz, Sara; Wagenaar, Alexander C

    2016-08-01

    To investigate the effects of state minimum wage laws on low birth weight and infant mortality in the United States. We estimated the effects of state-level minimum wage laws using a difference-in-differences approach on rates of low birth weight (minimum wage above the federal level was associated with a 1% to 2% decrease in low birth weight births and a 4% decrease in postneonatal mortality. If all states in 2014 had increased their minimum wages by 1 dollar, there would likely have been 2790 fewer low birth weight births and 518 fewer postneonatal deaths for the year.

  15. Determination of low molecular weight thiols using monobromobimane fluorescent labeling and high-performance liquid chromatography

    Fahey, Robert C.; Newton, Gerald L.

    1988-01-01

    Methods are described for the preparation and high-performance liquid chromatography (HPLC) analysis of monobromobimane derivatives of low molecular weight thiols in extracts of biological samples. Typical problems encountered in the development and application of these methods are discussed. Analysis of mung bean extract is used as an example.

  16. Low-molecular-weight heparin in the treatment of patients with venous thromboembolism

    tenCate, JW; Buller, HR; Gent, M; Hirsh, J; Prins, MH; Baildon, R; Lensing, AWA; Anderson, DR; vanBeek, EJR; Fiesinger, JN; Tijssen, JGP; vanBarneveld, A; Eimers, LT; Graafsma, YP; Hettiarachchi, R; Hutten, B; Redekop, K; Haley, S; LIberale, L; Finch, T; Whittaker, S; Wilkinson, L; Prandoni, P; Villalta, S; Girolami, B; Bagatella, P; Rossi, L; Girolami, A; Piovella, F; Barone, M; Beltrametti, C; Serafini, S; Siragusa, S; Ascari, E; Kovacs, MJ; Morrow, B; Kovacs, J; Kuijer, PMM; Koopman, MMW; Jagt, H; Weitz, J; Kearon, C; Biagioni, L; Haas, S; Lossner, F; Spengel, FA; Berger, M; Demers, C; Poulin, J; vanderMeer, J; Que, GTH; Smid, WM; Robinson, KS; Boyle, E; Leclerc, [No Value; StJacques, B; Finkenbine, S; Gallus, AS; Cohlan, D; Rich, C; Brandjes, DPM; Hoefnagel, CA; deRijk, M; Turkstra, F; Desjardins, L; CoteDesjardins, J; Couture, L; Ruel, M; Villenueve, J; Geerts, WH; Jay, RM; Code, EKI; Turpie, AGG; Johnson, J; Nguyen, P; Cusson, [No Value; Roy, S; Wells, PS; Bormanis, J; Goudie, D; Cruickshank, M; vonLewinski, M; Monreal, M; Sahuquillo, JC; Lafoz, E; Simonneau, G; Parent, F; Jagot, J; Douketis, JD; Kinnon, K; Ginsberg, JS; BrillEdwards, P; Donovan, D; Ockelford, PA; Kassis, J; Bornais, S; Planchon, B; ElKouri, D; Pistorius, MA; Escribano, M; Garrido, G; Chesterman, CN; Chong, BH; Pritchard, S; Cade, JF; Bynon, T; Stanford, J; Brien, WM; Palmer, B; Faivre, R; Petiteau, B; Manucci, PM; Moia, M; Bucciarelli, P

    1997-01-01

    Background Low-molecular-weight heparin is known to be safe and effective for the initial Treatment of patients with proximal deep-vein thrombosis. However, its application to patients with pulmonary embolism or previous episodes of thromboembolism has not been studied. Methods We randomly assigned

  17. Reversible, high molecular weight palladium and platinum coordination polymers based on phosphorus ligands

    Paulusse, J.M.J.; Huijbers, J.P.J.; Sijbesma, R.P.

    2005-01-01

    A general strategy for the preparation and characterization of high molecular weight coordination polymers based on bifunctional phosphorus ligands and palladium or platinum dichloride is described. Metal-to-ligand stoichiometry is of key importance for the formation of linear coordination polymers

  18. Reversible, High Molecular Weight Palladium and Platinum Coordination Polymers Based on Phosphorus Ligands

    Paulusse, Jos Marie Johannes; Huijbers, Jeroen P.J.; Sijbesma, Rint P.

    2005-01-01

    A general strategy for the preparation and characterization of high molecular weight coordination polymers based on bifunctional phosphorus ligands and palladium or platinum dichloride is described. Metal-to-ligand stoichiometry is of key importance for the formation of linear coordination polymers

  19. Low-molecular-weight poly-carboxylate as crystal growth modifier in ...

    Biomineralization; growth modifier; amino acid; low-molecular-weight chiral poly- carboxylate; calcium ... They are also used as gravity sensors, for metal storage and .... The pH of the solutions was maintained at ~10⋅0 for different periods of ...

  20. Differential Modulation of Cellular Bioenergetics by Poly(L-lysine)s of Different Molecular Weights

    Hall, Arnaldur; Wu, Lin-Ping; Parhamifar, Ladan

    2015-01-01

    Poly(L-lysine)s (PLLs), and related derivatives, have received considerable attention as nonviral vectors. High molecular weight PLLs (H-PLLs) are superior transfectants compared with low Mw PLLs (L-PLLs), but suggested to be more cytotoxic. Through a pan-integrated metabolomic approach using Sea...

  1. Dependence of negative muon depolarization on molecular weight and temperature in organic compounds

    Djuraev, A.A.; Evseev, V.S.; Obukhov, Yu.V.; Roganov, V.S.

    2009-01-01

    An atomic capture of negative muons in the aliphatic spirit series, the dependence of muon rest polarization on the molecular weight of spirit have been studied. The temperature dependence of depolarization in benzole and styrene has been obtained. The results on depolarization are being interpreted basing on notions about chemical interactions of mesic atoms in organic compounds. (author)

  2. Methanol-induced chain termination in poly(3-hydroxybutyrate) biopolymers: molecular weight control

    A systematic study was performed to demonstrate the impact of methanol (MeOH) on poly(3-hydroxybutyrate) (PHB) synthesis and molecular weight (MW) control. Glycerine (init. conc. = 1.0%; w/v), was used as the primary carbon source in batch-culture fermentations with varying concentrations (0 to 0.85...

  3. A global survey of low-molecular weight carbohydrates in lentils

    Lentils contain a range of low-molecular weight carbohydrates (LMWC); however, those have not been well characterized. The objectives of this study were to (1) determine the concentrations of LMWC in lentils grown in six locations, and (2) identify any genetic and environmental effects on those LMWC...

  4. The adhesive properties of chlorinated ultra-high molecular weight polyethylene

    Menting, H.N.A.M.; Voets, P.E.L.; Lemstra, P.J.

    1995-01-01

    Ultra-high molecular weight polyethylene (UHMW-PE) is well known for its abrasion and chemical resistance. Recently we developed a new application for UHMW-PE as a liner in elastomeric hoses. It was found that the adhesion between UHMW-PE and elastomers such as ethylene-propylene-diene monomer

  5. Extension induced phase separation and crystallization in semidilute solutions of ultra high molecular weight polyethylene

    Wingstrand, Sara Lindeblad; Imperiali, Luna; Stepanyan, Roman

    2018-01-01

    Abstract We investigate the influence of controlled uniaxial extension on various flow induced phenomena in semidilute solutions of ultra high molecular weight polyethylene (UHMwPE). Concentrations range from 9 w% to 29 w% and the choice of solvent is paraffin oil (PO). The start-up extensional b...

  6. Nanometer size wear debris generated from ultra high molecular weight polyethylene in vivo

    Lapčíková, Monika; Šlouf, Miroslav; Dybal, Jiří; Zolotarevova, E.; Entlicher, G.; Pokorný, D.; Gallo, J.; Sosna, A.

    2009-01-01

    Roč. 266, 1-2 (2009), s. 349-355 ISSN 0043-1648 R&D Projects: GA MŠk 2B06096 Institutional research plan: CEZ:AV0Z40500505 Keywords : ultra high molecular weight polyethylene * nanometer size wear debris * morphology of wear particles Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.771, year: 2009

  7. Tumor microvascular changes in antiangiogenic treatment : Assessment by magnetic resonance contrast media of different molecular weights

    Turetschek, K; Preda, A; Novikov, [No Value; Brasch, RC; Weinmann, HJ; Wunderbaldinger, P; Roberts, TPL

    Purpose: To test magnetic resonance (MR) contrast media of different molecular weights (MWs) for their potential to characterize noninvasively microvascular changes in an experimental tumor treatment model. Materials and Methods: MD-MBA-435, a poorly differentiated human breast cancer cell line, was

  8. Safety of low-molecular-weight heparin in pregnancy: a systematic review

    Sanson, B. J.; Lensing, A. W.; Prins, M. H.; Ginsberg, J. S.; Barkagan, Z. S.; Lavenne-Pardonge, E.; Brenner, B.; Dulitzky, M.; Nielsen, J. D.; Boda, Z.; Turi, S.; Mac Gillavry, M. R.; Hamulyák, K.; Theunissen, I. M.; Hunt, B. J.; Büller, H. R.

    1999-01-01

    Unfractionated heparin (UFH) remains the anticoagulant of choice during pregnancy. Low-molecular-weight heparins (LMWH) are an attractive alternative to UFH due to their logistic advantages and their association with a lower incidence of osteoporosis and HIT. We reviewed all published clinical

  9. Rheological properties of poly(vinylpiyrrolidone) as a function of molecular weight

    Marani, Debora; Sudireddy, Bhaskar Reddy; Kiebach, Wolff-Ragnar

    2014-01-01

    Different grades of poly (vinylpyrrolidone) (PVP) were studied as dispersant for gadolinium doped cerium oxide (CGO) in ethanol-based colloidal dispersions. The average molecular weights Mw, Mn, and Mz were determined by gel permeation chromatography (GPC), and then used in a numerical method...

  10. Polyacrylamide molecular weight and phosphogypsum effects on infiltration and erosion in semi-arid soils

    Seal formation at the surface of semi-arid soils during rainstorms reduces soil infiltration rate (IR) and causes runoff and erosion. Surface application of dry anionic polyacrylamide (PAM) with high molecular weight (MW) has been found to be effective in stabilizing soil aggregates, and decreasing ...

  11. Control of radio degradation of natural polymers by measurement of viscosity and molecular weight determination

    Nabinger Machado, Patricia; Cerchietti, Maria Luciana; Mondino, Angel V.; Smolko, Eduardo E.

    2009-01-01

    Applications are now being made in various fields of oligosaccharides obtained by the depolymerization of large molecules such as natural alginates, carrageenan, pectin and chitosan. Find use in various disciplines such as crop production, sanitation, pharmacy, cosmetics, etc. Given the diversity of origins of these materials, almost all of marine origin, was the need for universal methods for recognition and composition, then the possible ways to get processed. A centralized program by the IAEA is promoting the use of ionizing radiation for these changes. This paper resents the calculations used to obtain the molecular weight of polysaccharides from determinations of viscosity. It has been found the molecular weight of sodium alginate and kappa-carrageenan irradiated with cobalt-60 gamma rays at doses between 2 and 35 kGy in solid state. We used a capillary Cannon Viscometer Ubbelohde-type and a protocol for standardized calculation procedure for this purpose. Were obtained reading times for passage through the capillary Viscometer, with various concentrations of polymer solutions of virgin material and the irradiated and from there calculated the relative viscosities, specific, inherent, reduced and intrinsic and then using the ratio of Mark-Houwink-SAKURADA calculate the viscosity average molecular weight of the different polymers. The changes found in the molecular weights by radio-depolymerization reach two orders of magnitude in some cases giving oligosaccharides of 8-12 monomer units. It is considered that this depolymerization method is effective and inexpensive compared to enzymatic or chemical methods. (author)

  12. Separation and analysis of low molecular weight plasticizers in poly(vinyl chloride) tubes

    Wang, Qian; Storm, Birgit Kjærside

    2005-01-01

    ) and thermogravimetric analysis (TGA), as well as by studying the extracted low molecular weight plasticizers by gas chromatography/mass spectroscopy (GC/MS) and GC. It was found that the simple room temperature extraction in chloroform showed the best separation of plasticizers from the PVC matrix. Close results...

  13. Venous thromboembolism in pregnancy: prophylaxis and treatment with low molecular weight heparin

    Andersen, Anita Sylvest; Berthelsen, Jørgen G; Bergholt, Thomas

    2010-01-01

    OBJECTIVE: To evaluate the safety of individually dosed low molecular weight heparin (LMWH) for prophylaxis and treatment of thromboembolic complications in pregnancy. DESIGN: Cohort study with a chronologic register-based control group. SETTING: Department of Obstetrics and Gynecology, Hillerød ...

  14. Venous thromboembolism in pregnancy: prophylaxis and treatment with low molecular weight heparin

    Andersen, Anita Sylvest; Berthelsen, Jørgen G.; Bergholt, Thomas

    2010-01-01

    OBJECTIVE: To evaluate the safety of individually dosed low molecular weight heparin (LMWH) for prophylaxis and treatment of thromboembolic complications in pregnancy. DESIGN: Cohort study with a chronologic register-based control group. SETTING: Department of Obstetrics and Gynecology, Hillerød...

  15. Role of Molecular Weight on the Mechanical Device Properties of Organic Polymer Solar Cells

    Bruner, Christopher; Dauskardt, Reinhold

    2014-01-01

    important implications for long-Term reliability, manufacturing, and future applications of electronic organic thin films. In this work, we show that the molecular weight rr-P3HT in organic solar cells can also significantly change the internal cohesion

  16. Molecular weight control in emulsion polymerization by catalytic chain transfer : a reaction engineering approach

    Smeets, N.M.B.; Meda, U.S.; Heuts, J.P.A.; Keurentjes, J.T.F.; Herk, van A.M.; Meuldijk, J.

    2007-01-01

    For the application of catalytic chain transfer in (mini)emulsion polymerization, catalyst partitioning and deactivation are key parameters that govern the actual catalyst concentration at the locus of polymerization and consequently the final molecular weight distribution. A global model, based on

  17. Adhesives, fillers & potting compounds: Special report molecular weight determinations of dimethypolysiloxane polymers

    Luthey, Z.A.

    1968-09-03

    Using a Mechrolab Vapor Phase Osmometer and a Hallikainen Automatic Membrane Osmometer the number-average molecular weight of two samples of dimethylpolysiloxane - 2300 and 8000 cstk - as well as samples made by mixing the two previously mentioned materials were determined.

  18. The effect of chitosan molecular weight on the properties of alginate ...

    Purpose: The aim of the present study was to investigate the effect of chitosan molecular weight on size, size distribution, release rate, mucoadhesive properties and electrostatic bonding of alginate/chitosan microparticles containing prednisolone. Methods: Three mucoadhesive alginate/chitosan microparticle formulations, ...

  19. Dietary factors associated with plasma high molecular weight and total adiponectin levels in apparently healthy women

    Yannakoulia, Mary; Yiannakouris, Nikos; Melistas, Labros; Fappa, Evaggelia; Vidra, Nikoletta; Kontogianni, Meropi D; Mantzoros, Christos S

    2008-01-01

    OBJECTIVE: Our aim was to investigate associations between dietary factors and high molecular weight (HMW) as well as total adiponectin in a sample of apparently healthy adult Mediterranean women. DESIGN AND METHODS: Two hundred and twenty women were enrolled in this study. Anthropometric and body

  20. Preparation of Low Molecular Weight Chitosan by Radiation and its Application for Plant Growth Promoter. Chapter 10

    Darwis, D.; Puspitasari, T.; Iramani, D.; Susilowati, Sri; Pangerteni, D.S., E-mail: darmawan_p3tir@batan.go.id [National Nuclear Energy Agency, Centre for Application of Isotopes and Radiation Technology (Indonesia)

    2014-07-15

    Chitosan was prepared through the alkaline deacetylation of chitin from shrimp shell waste. Chitosan with a degree of deacetylation of about 70% was produced by hot alkaline deacetylation (DDA) at 90°C for 8 hours or at room temperature deacetylation for 7 days. Through these processes, chitosan with an average molecular weight (Mw) of 141 k Dalton was obtained. Low molecular weight chitosan, Mw 14 k Dalton called “Fitosan” was prepared by irradiating chitosan using gamma rays at a dose of 75 kGy. The results showed that gamma irradiation is an effective method of degrading chitosan by cleavages of glycosidic bond. To improve crop yields and suppress diseases due to virus, bacteria, and fungi, Fitosan was successfully applied to chili, potato, and soybean. Socio-economic impacts of the use of Fitosan on the plants include increased income and improvement of the welfare of farmers. (author)

  1. Effect of Addition of Concentrated Proteins and Seminal Plasma Low Molecular Weight Proteins in Freezing and Thawing of Equine Semen

    Fagundes, B.

    2011-07-01

    Full Text Available Difficulties in obtaining equine frozen semen with potential fertility are recognized. This study was designed to investigate the effect of seminal plasma on frozen/thawing of eight stallion semen from different breed using the following treatments: Seminal plasma with ten-fold concentrated proteins with molecular weight above 10 kDa on frozen extender; Part of seminal plasma with proteins under 10 kDa on frozen extender; Conventional freezing, using whole seminal plasma on frozen extender. Using the parameter of 30% of seminal motility post-thawing as index of good freezability, it was verified an increased percentage of stallions that presented good freezability when semen was frozen with seminal plasma containing ten-fold concentrated proteins with molecular weight above 10 kDa on frozen extender. These results, suggested the use of seminal plasma concentrated proteins from own stallion to freezing/thawing semen.

  2. Blends of low molecular weight of poly lactic acid (PLA) with gondorukem (gum rosin)

    Kaavessina, Mujtahid; Distantina, Sperisa; Chafidz, Achmad; Utama, Aditya; Anggraeni, Venisa Mega Puteri

    2018-02-01

    The utilization of plastic was increasing as well as the increasing its demand in wide range application. Consequently, the number of plastic litter will increase and make more serious environmental problems. This research concerns to minimize waste problems by designing biodegradable plastic. In this research, biodegradable plastic was made of poly lactic acid (PLA) and gondorukem (Gum rosin, Resina colophonium) as the plasticizer. The effect of gondorukem towards PLA properties such as rheology and degradability was investigated. The research divided into two steps: (i) the polycondensation of lactic acid (LA) and (ii) modification of obtained poly lactic acid. In the first step, polycondensation was done in N2 atmosphere (138°C) for 30 hours and added 0.1 %w of SnCl2 as catalyst. Bulk modification was conducted by blending of gondurukem in varied weight (0.5, 1, and 2 g in 10 g of PLA). Furthermore, the modified PLA was analyzed its molecular structure, biodegradability and rheological property. The presence of gondorukem enhanced the biodegradability of poly lactic acid. Gondorukem could act as the plasticizer. It is confirmed that the complex viscosity of PLA melt decreased upon the addition of gondorukem

  3. Hofmeister effect on thermo-responsive poly(propylene oxide): Role of polymer molecular weight and concentration.

    Moghaddam, Saeed Zajforoushan; Thormann, Esben

    2016-03-01

    Although a vast amount of research has been dedicated to investigate the Hofmeister effect on the stability of polymer solutions, a clear understanding of the role of polymer properties in this phenomenon is still missing. Here, the Hofmeister effect of NaCl (destabilizing) and NaSCN (stabilizing) salts on aqueous solutions of poly(propylene oxide) (PPO) is studied. Four different molecular weights of PPO were investigated, to determine how the variation in the polymer coil size affects the Hofmeister effect. The investigation was further conducted for different PPO concentrations, in order to understand the effect of inter-chain interactions on the response to addition of salt. The temperature-driven phase separation of the solutions was monitored by differential scanning calorimetry, which provides the precise value of the phase separation temperature, as well as the enthalpy change accompanied with the transition. It was observed that increasing the molecular weight weakens the effect of the both salts, which is interpreted in terms of a scaling law between the molecular weight and the accessible surface area of the polymers. Increasing the PPO concentration further diminished the NaCl effect, but amplified the NaSCN effect. This difference is attributed to an electrostatic stabilization mechanism in the case of NaSCN. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Molecularly Imprinted Polymer Waveguides for Direct Optical Detection of Low-Molecular-Weight Analytes

    Sharma, N.; Petri, C.; Jonas, U.; Bach, M.; Tovar, G.; Mrkvová, Kateřina; Vala, Milan; Homola, Jiří; Knoll, W.; Dostálek, J.

    2014-01-01

    Roč. 215, č. 23 (2014), s. 2295-2304 ISSN 1022-1352 R&D Projects: GA ČR GBP205/12/G118 Institutional support: RVO:67985882 Keywords : Label-free biosensors * Molecularly imprinted polymers * Hydrogels Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 2.616, year: 2014

  5. Ingestion of High Molecular Weight Carbohydrate Enhances Subsequent Repeated Maximal Power: A Randomized Controlled Trial.

    Jonathan M Oliver

    Full Text Available Athletes in sports demanding repeat maximal work outputs frequently train concurrently utilizing sequential bouts of intense endurance and resistance training sessions. On a daily basis, maximal work within subsequent bouts may be limited by muscle glycogen availability. Recently, the ingestion of a unique high molecular weight (HMW carbohydrate was found to increase glycogen re-synthesis rate and enhance work output during subsequent endurance exercise, relative to low molecular weight (LMW carbohydrate ingestion. The effect of the HMW carbohydrate, however, on the performance of intense resistance exercise following prolonged-intense endurance training is unknown. Sixteen resistance trained men (23±3 years; 176.7±9.8 cm; 88.2±8.6 kg participated in a double-blind, placebo-controlled, randomized 3-way crossover design comprising a muscle-glycogen depleting cycling exercise followed by ingestion of placebo (PLA, or 1.2 g•kg•bw-1 of LMW or HMW carbohydrate solution (10% with blood sampling for 2-h post-ingestion. Thereafter, participants performed 5 sets of 10 maximal explosive repetitions of back squat (75% of 1RM. Compared to PLA, ingestion of HMW (4.9%, 90%CI 3.8%, 5.9% and LMW (1.9%, 90%CI 0.8%, 3.0% carbohydrate solutions substantially increased power output during resistance exercise, with the 3.1% (90% CI 4.3, 2.0% almost certain additional gain in power after HMW-LMW ingestion attributed to higher movement velocity after force kinematic analysis (HMW-LMW 2.5%, 90%CI 1.4, 3.7%. Both carbohydrate solutions increased post-exercise plasma glucose, glucoregulatory and gut hormones compared to PLA, but differences between carbohydrates were unclear; thus, the underlying mechanism remains to be elucidated. Ingestion of a HMW carbohydrate following prolonged intense endurance exercise provides superior benefits to movement velocity and power output during subsequent repeated maximal explosive resistance exercise. This study was registered

  6. Relationship between molecular weight, monosaccharide composition and immunobiologic activity of Astragalus polysaccharides.

    Jiang, Yiping; Qi, Xiaohui; Gao, Kai; Liu, Wenjun; Li, Na; Cheng, Ningbo; Ding, Gang; Huang, Wenzhe; Wang, Zhenzhong; Xiao, Wei

    2016-10-01

    Four Astragalus polysaccharides (APS1-APS4) were isolated from the water extract of Radix Astragali and purified through ethanol precipitation with 20 %, 40 %, 60 % and 80 % ethanol, respectively. The total sugar content was measured by sulfuric acid-phenol method. Their molecular weight was determined using high performance gel permeation chromatography (HPGPC) and their monosaccharide composition was analyzed by reversed-phase high performance liquid chromatography (HPLC) after pre-column derivatization. Then the immunobiologic activity of APS was evaluated by the experiment of spleen lymphocytes proliferation in vitro. The data suggested that precipitation by different concentration of ethanol will obtain different molecular weight APS, the higher concentration of ethanol the smaller molecular weight for APS. The molecular weights of four APS were 257.7 kDa, 40.1 kDa, 15.3 kDa and 3.2 kDa. Monosaccharide composition analysis indicated that APS1 consisted of glucose only, and APS2 all consisted of arabinose. APS3 consisted of rhamnose, glucose, galactose and arabinose and APS4 consisted of galactose and arabinose, in a molar ratio of 1:10.76:6.55:12 and 3.02:1. The result of immunobiologic activity assay showed that both APS2 and APS3 can effectively stimulate normal spleen lymphocyte proliferation in vitro. Apart from this, the effect of APS2 also showed dose dependent tendency from 6.25 μg/mL to 800 μg/mL. The result of this research indicated that Astragalus polysaccharides, which consist of arabinose and their molecular weight between 15.2 kDa to 40.1 kDa, neither too high nor too low, had significant immune activity.

  7. Influence of sugars on the dry-weight increase of gamma irradiated Jerusalem artichoke tuber's tissue

    Schaeverbeke-Sacre, J.

    1976-01-01

    Jerusalem artichoke tuber's explants after a γ irradiation of 6000 rads couldn't proliferate in a growth medium containing glucose and indolyl acetic acid; their dry weight is increased by an accumulation of sugars [fr

  8. Hydrodynamic characterization and molecular weight estimation of ultrasonically sheared DNA; Caracterizacion hidrodinamica y estimacion de pesos moleculares de DNA degradado por ultrasonidos

    Casal, J I; Garces, F; Garcia-Sacristan, A

    1981-07-01

    The sedimentation coefficients and intrinsic viscosities of ultrasonically sheared calf thymus DNA have been determined. The molecular weight estimation according to this parameters have been compared with the ones obtained from the electrophoretic migration rates based on the calibration proposed using the known molecular weight restriction fragments of X-ENA. (Author) 35 refs.

  9. Effects of molecular weight of PVA on formation, stability and deformation of compound droplets for ICF polymer shells

    Liu, Meifang; Zheng, Yueqing; Li, Jie; Chen, Sufen; Liu, Yiyang; Li, Jing; Li, Bo; Zhang, Zhanwen

    2017-01-01

    Sphericity and wall thickness uniformity are some of the hardest specifications to fulfill, as required by inertial confined fusion (ICF) research for polymer shells prepared by the microencapsulation technique. Driven by the need to control the deformation of compound droplets, the effects of the molecular weight of poly(vinyl alcohol) (PVA) on the formation and stability of the droplets, as well as the sphericity and wall thickness uniformity of the resulting shells, were investigated. On increasing the molecular weight of the PVA, the densities of the external water phases (W2) are almost the same, but the viscosity of the W2 phase increases more quickly than the interfacial tension. This makes the detaching force increase more quickly than the upward one, causing the formation of compound droplets and detachment from the oil tube. On the other hand, the increase in interfacial tension makes the maximum pressures ( P max) in the O phase (O) of the compound droplets increase, causing them to rupture easily and decreasing their stability. However, for PVA with the same molecular weight, the viscous shear force in the flowing field reduces the role of gravity and makes the inner water droplet move towards the center of the compound droplet, decreasing its P max in the flowing field and improving its stability. Moreover, during the solidifying process, the viscous shear force increases more quickly than the interfacial tension force due to the quicker increase in viscosity with an increase in the molecular weight of the PVA. The increase in the viscous shear force can make the droplets deform, resulting in a decrease in their sphericity. However, the appropriate viscous shear force can also center the compound droplet—although they become decentered when the viscous shear force is too large, leading to the wall thickness uniformity increasing at first before decreasing quickly. The results presented in this work provide a more in-depth understanding of the

  10. Plasticization of poly(lactic acid) using different molecular weight of Poly(ethylene glycol)

    Septevani, Athanasia Amanda; Bhakri, Samsul

    2017-11-01

    Poly (lactic acid) (PLA) has been known as an excellent candidate for developing the future bioplastic due to its biodegradability and competitive price. However, inherent brittleness and low thermal stability of PLA have limited its applications. Considerable studies have been developed to improve the flexibility of PLA, in which blending PLA with various plasticizers has been identified as a cost-effective way to lower glass-transition temperature (Tg) and thus improve its elongation property. In this study, PLA was modified by incorporating poly(ethylene glycol) as a plasticizer with different molecular weights (M¯w 400, 1000, and 6000, called respectively as PEG 400, PEG 1000, and PEG 6000) via a solvent-casting blend method. FTIR was used for analyzing the chemical interaction while TGA and DSC measured the thermal behavior of PLA/PEG. The results indicated that the addition of lower M¯w (PEG 400 and PEG 1000) could reduce the Tg due to the enhancement of chain mobility of PLA with PEG and so driving into a more amorphous states resulted reduction of melting temperature (Tm) compared to the neat PLA. Further, at a higher M¯w of PEG 6000, the longer chain of ethylene glycol, in contrast, resulted a gradual increase in the Tg as well as Tm where the value went back to the point of neat PLA compared to the other lower molecular weight of PLA. This was due to the decrease in polymer miscibility with the increasing of M¯w. In terms of thermal stability, the addition of PEG exhibited two step degradation behavior while the neat PLA only possessed single step degradation. The presence of PEG could act as a protective barrier layer that could hinder the permeability of the volatile compound and product during decomposition reaction and thus could eventually delay and slower the degradation process. It was observed that the addition of PEG at higher M¯w (PEG1000 and PEG 6000) exhibited a higher second degradation temperature up to 380 °C.

  11. Short-term increase of body weight triggers immunological variables in dogs.

    Van de Velde, H; Janssens, G P J; Stuyven, E; Cox, E; Buyse, J; Hesta, M

    2012-01-15

    Overweight in dogs is, as in other companion animals, a major risk factor for several metabolic disorders. However, it is not yet known whether immunity is challenged by increased body weight in dogs. The aim of this study was to investigate the effect of a short-term increase in body weight on immunological variables in adult healthy beagle dogs. Sixteen dogs, divided into a control group (CG) and weight gain group (WGG), were included. During a period of 13 weeks, the CG was fed at maintenance energy requirement (MER), whereas the WGG received a double amount of food. After 13 weeks, blood samples were taken for immunological and biochemical analyses. Weight gain and increased body condition score in the WGG were accompanied by a significant higher leptin concentration. Weight gain increased the number of lymphocytes and immunoglobulins A and M and was responsible for a higher proliferation of peripheral blood mononuclear cells (PBMC). Short-term increase of body weight thus seems to trigger immunological variables in dogs. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Low molecular weight chitosan conjugated with folate for siRNA delivery in vitro: optimization studies

    Fernandes, Julio C; Qiu, Xingping; Winnik, Francoise M; Benderdour, Mohamed; Zhang, Xiaoling; Dai, Kerong; Shi, Qin

    2012-01-01

    The low transfection efficiency of chitosan is one of its drawbacks as a gene delivery carrier. Low molecular weight chitosan may help to form small-sized polymer-DNA or small interfering RNA (siRNA) complexes. Folate conjugation may improve gene transfection efficiency because of the promoted uptake of folate receptor-bearing cells. In the present study, chitosan was conjugated with folate and investigated for its efficacy as a delivery vector for siRNA in vitro. We demonstrate that the molecular weight of chitosan has a major influence on its biological and physicochemical properties, and very low molecular weight chitosan (below 10 kDa) has difficulty in forming stable complexes with siRNA. In this study, chitosan 25 kDa and 50 kDa completely absorbed siRNA and formed nanoparticles (≤220 nm) at a chitosan to siRNA weight ratio of 50:1. The introduction of a folate ligand onto chitosan decreased nanoparticle toxicity. Compared with chitosan-siRNA, folate-chitosan-siRNA nanoparticles improved gene silencing transfection efficiency. Therefore, folate-chitosan shows potential as a viable candidate vector for safe and efficient siRNA delivery. PMID:23209368

  13. Molecular-weight distributions of coal and petroleum asphaltenes from laser desorption/ionization experiments

    Ana R. Hortal; Paola Hurtado; Bruno Martinez-Haya; Oliver C. Mullins [Universidad Pablo de Olavide, Seville (Spain). Departamento de Sistemas Fisicos, Quimicos y Naturales

    2007-09-15

    Molecular-weight distributions (MWDs) of asphaltenes extracted from coal and petroleum have been measured in laser desorption/ionization (LDI) mass spectrometric experiments. The dried-droplet and solvent-free sample preparation methods are compared. The coal asphaltenes have a relatively narrow MWD (full width 150 amu) with an average molecular weight of 340 amu. The petroleum asphaltenes display a broader MWD (full width 300 amu) and are heavier on average (680 amu). The LDI spectra also provide evidence for the formation of noncovalent clusters of the two types of asphaltenes during the desorption process. Petroleum and coal asphaltenes exhibit aggregation as do large model polycyclic aromatic hydrocarbons (PAHs) with five or more fused rings also included in the study. Smaller PAHs (pyrene) exhibit less aggregation, especially when alkane-chain substituents are incorporated to the molecular structure. This indicates that asphaltenes possess large PAHs and, according to the relatively small molecular weights observed, that there is a preponderance of asphaltene molecules with only a single fused ring system. The coal asphaltenes present a significantly smaller propensity toward aggregation than their crude oil counterparts. This finding, coupled with the fact that (1) alkanes inhibit aggregation in LDI and (2) petroleum asphaltenes possess much more alkane carbon, indicates that coal asphaltenes have smaller PAHs on average than petroleum asphaltenes. This is further corroborated by the stronger ultraviolet absorbance of the coal asphaltenes at wavelengths shorter than 400 nm. 32 refs., 8 figs.

  14. The effect of low molecular weight multifunctional additives on heavy oil viscosity

    Oldenburg, T.B.P.; Yarranton, H.W.; Larter, S.R. [Calgary Univ., AB (Canada)

    2010-07-01

    Crude oils contain many small multifunctional low molecular weight components that act as linking molecules between larger functionalized species. The linkage molecules have a significant impact on the flow properties of hydrocarbon systems. This study investigated the use of a low molecular weight multiheteroatom species (LMWMH) as a molecular Velcro linking high molecular weight components together. LMWMH species were added to Albertan bitumens and heavy oil, and their impact on viscosity was investigated. Results of the experimental studies were then compared with the effects of hydrocarbon solvents on similar samples. The LMWMH species included bifunctional species and analogous alkyl and aryl monoamines that acted as blocking molecules to hinder the association of larger petroleum species. Density and viscosity measurements were conducted. A correlation method was used to predict the viscosity of the solvent-diluted heavy oil and bitumen samples. The study showed that of the tested additives, only aniline demonstrated an additional viscosity-reducing effect. The aniline inhibited asphaltene association and is a promising candidate for enhanced in-situ bitumen viscosity reduction. 23 refs., 4 tabs.

  15. Total and high molecular weight adiponectin are elevated in patients with Laron syndrome despite marked obesity.

    Kanety, Hannah; Hemi, Rina; Ginsberg, Shira; Pariente, Clara; Yissachar, Eleanor; Barhod, Ehud; Funahashi, Tohru; Laron, Zvi

    2009-12-01

    Patients with Laron syndrome (LS; primary GH insensitivity) caused by molecular defects of the GH receptor gene, are characterized by dwarfism, profound obesity, and hyperlipidemia. The aim of the current study was to evaluate adiponectin levels in LS, as obesity is known to be associated with low adiponectin. We studied nine untreated LS adult patients (5 males, 4 females) and six girls with LS receiving once-daily treatment by IGF1. Total and high molecular weight (HMW) adiponectin levels, adiponectin multimers distribution, and metabolic indices were analyzed in serum samples obtained during several years of follow-up. Adiponectin levels in the severely obese adult LS patients (percent body fat; females 61.0+/-2.5%, males 40.6+/-8.1%) were two- to three-fold higher than those reported for subjects of corresponding age, gender and degree of adiposity. Total adiponectin was significantly higher in females compared with males (21.4+/-3.5 vs 10.2+/-4.6 microg/ml, P<0.001). The elevated adiponectin in LS subjects was associated with an increased abundance of the HMW isoform, and positively correlated with body fat percentage (r=0.65, P=0.017) and leptin (r=0.65, P=0.012). There was no correlation between adiponectin levels (total and HMW) and the degree of insulin resistance in LS subjects or their blood lipids levels. Adiponectin was also high in young girls with LS (22.9+/-7.4 microg/ml) and did not change during long-term IGF1 replacement therapy. Adiponectin hypersecretion in LS, despite profound obesity, suggests that GH activity may negatively impact adiponectin secretion from adipocytes.

  16. Individual Importance Weighting of Domain Satisfaction Ratings does Not Increase Validity.

    Rohrer, Julia M; Schmukle, Stefan C

    2018-01-01

    Bottom-up models of life satisfaction are based on the assumption that individuals judge the overall quality of their lives by aggregating information across various life domains, such as health, family, and income. This aggregation supposedly involves a weighting procedure because individuals care about different parts of their lives to varying degrees. Thus, composite measures of well-being should be more accurate if domain satisfaction scores are weighted by the importance that respondents assign to the respective domains. Previous studies have arrived at mixed conclusions about whether such a procedure actually works. In the present study, importance weighting was investigated in the Panel Study of Income Dynamics (PSID; N = 5,049). Both weighted composite scores and moderated regression analyses converged in producing the conclusion that individual importance weights did not result in higher correlations with the outcome variable, a global measure of life satisfaction. By contrast, using weights that vary normatively across domains (e.g., assigning a larger weight to family satisfaction than to housing satisfaction for all respondents) significantly increased the correlation with global life satisfaction (although incremental validity was rather humble). These results converge with findings from other fields such as self-concept research, where evidence for individual importance weighting seems elusive as best.

  17. Individual Importance Weighting of Domain Satisfaction Ratings does Not Increase Validity

    Rohrer, Julia M.; Schmukle, Stefan C.

    2018-01-01

    Bottom-up models of life satisfaction are based on the assumption that individuals judge the overall quality of their lives by aggregating information across various life domains, such as health, family, and income. This aggregation supposedly involves a weighting procedure because individuals care about different parts of their lives to varying degrees. Thus, composite measures of well-being should be more accurate if domain satisfaction scores are weighted by the importance that respondents assign to the respective domains. Previous studies have arrived at mixed conclusions about whether such a procedure actually works. In the present study, importance weighting was investigated in the Panel Study of Income Dynamics (PSID; N = 5,049). Both weighted composite scores and moderated regression analyses converged in producing the conclusion that individual importance weights did not result in higher correlations with the outcome variable, a global measure of life satisfaction. By contrast, using weights that vary normatively across domains (e.g., assigning a larger weight to family satisfaction than to housing satisfaction for all respondents) significantly increased the correlation with global life satisfaction (although incremental validity was rather humble). These results converge with findings from other fields such as self-concept research, where evidence for individual importance weighting seems elusive as best. PMID:29652406

  18. Effect of molecular weight and glass transition on relaxation and release behaviour of poly(DL-lactic acid) tablets

    Steendam, R.; Van Steenbergen, M.J.; Hennink, W.E.; Frijlink, H.W.; Lerk, C.F.

    2001-01-01

    Different molecular weight grades of poly(DL-lactic acid) were applied as release controlling excipients in tablets for oral drug administration. The role of molecular weight and glass transition in the mechanism of water-induced volume expansion and drug release of PDLA tablets was investigated.

  19. Local injection of high-molecular hyaluronan promotes wound healing in old rats by increasing angiogenesis.

    Huang, Luying; Wang, Yi; Liu, Hua; Huang, Jianhua

    2018-02-02

    Impaired angiogenesis contributes to delayed wound healing in aging. Hyaluronan (HA) has a close relationship with angiogenesis and wound healing. However, HA content decreases with age. In this study, we used high molecular weight HA (HMW-HA) (1650 kDa), and investigated its effects on wound healing in old rats by local injection. We found that HMW-HA significantly increases proliferation, migration and tube formation in endothelial cells, and protects endothelial cells against apoptosis. Local injection of HMW-HA promotes wound healing by increasing angiogenesis in old rats. HMW-HA increases the phosphorylation of Src, ERK and AKT, leading to increased angiogenesis, suggesting that local injection of HMW-HA promotes wound healing in elderly patients.

  20. Low Molecular Weight Heparin Improves Endothelial Function in Pregnant Women at High Risk of Preeclampsia.

    McLaughlin, Kelsey; Baczyk, Dora; Potts, Audrey; Hladunewich, Michelle; Parker, John D; Kingdom, John C P

    2017-01-01

    Low molecular weight heparin (LMWH) has been investigated for the prevention of severe preeclampsia, although the mechanisms of action are unknown. The objective of this study was to investigate the cardiovascular effects of LMWH in pregnant women at high risk of preeclampsia. Pregnant women at high risk of preeclampsia (n=25) and low-risk pregnant controls (n=20) at 22 to 26 weeks' gestation underwent baseline cardiovascular assessments. High-risk women were then randomized to LMWH or saline placebo (30 mg IV bolus and 1 mg/kg subcutaneous dose). Cardiovascular function was assessed 1 and 3 hours post randomization. The in vitro endothelial effects of patient serum and exogenous LMWH on human umbilical venous endothelial cells were determined. High-risk women demonstrated a reduced cardiac output, high resistance hemodynamic profile with impaired radial artery flow-mediated dilation compared with controls. LMWH increased flow-mediated dilation in high-risk women 3 hours after randomization compared with baseline and increased plasma levels of placental growth factor, soluble fms-like tyrosine kinase-1, and myeloperoxidase. Serum from high-risk women impaired endothelial cell angiogenesis and increased PlGF-1 and PlGF-2 transcription compared with serum from low-risk controls. Coexposure of high-risk serum with LMWH improved the in vitro angiogenic response such that it was equivalent to that of low-risk serum and promoted placental growth factor secretion. LMWH improves maternal endothelial function in pregnant women at high risk of developing preeclampsia, possibly mediated through increased placental growth factor bioavailability. © 2016 American Heart Association, Inc.

  1. Low molecular weight thiols and thioredoxins are important players in Hg(II) resistance in Thermus thermophilus HB27.

    Norambuena, J; Wang, Y; Hanson, T; Boyd, J M; Barkay, T

    2017-11-17

    Mercury (Hg), one of the most toxic and widely distributed heavy metals, has a high affinity for thiol groups. Thiol groups reduce and sequester Hg. Therefore, low molecular weight and protein thiols may be important cell components used in Hg resistance. To date, the role of low molecular weight thiols in Hg-detoxification remains understudied. The mercury resistance ( mer ) operon of Thermus thermophilus suggests an evolutionary link between Hg(II) resistance and low molecular weight thiol metabolism. This mer operon encodes for an enzyme involved in methionine biosynthesis, Oah. Challenge with Hg(II) resulted in increased expression of genes involved in the biosynthesis of multiple low molecular weight thiols (cysteine, homocysteine, and bacillithiol), as well as the thioredoxin system. Phenotypic analysis of gene replacement mutants indicated that Oah contributes to Hg resistance under sulfur limiting conditions, and strains lacking bacillithiol and/or thioredoxins are more sensitive to Hg(II) than the wild type. Growth in presence of either a thiol oxidizing agent or a thiol alkylating agent increased sensitivity to Hg(II). Furthermore, exposure to 3 μM Hg(II) consumed all intracellular reduced bacillithiol and cysteine. Database searches indicate that oah2 is present in all Thermus spp. mer operons. The presence of a thiol related gene was also detected in some alphaprotobacterial mer operons, in which a glutathione reductase gene was present, supporting the role of thiols in Hg(II) detoxification. These results have led to a working model in which LMW thiols act as Hg(II) buffering agents while Hg is reduced by MerA. Importance The survival of microorganisms in presence of toxic metals is central to life's sustainability. The affinity of thiol groups to toxic heavy metals drives microbe-metal interactions and modulate metal toxicity. Mercury detoxification ( mer ) genes likely originated early in microbial evolution among geothermal environments. Little is

  2. Early pair housing increases solid feed intake and weight gains in dairy calves

    Costa, J. H. C.; Meagher, R. K.; von Keyserlingk, M. A. G.; Weary, D. M.

    2015-01-01

    Dairy calves have traditionally been kept in individual pens throughout the milk-feeding period. Social rearing is associated with increased solid feed intake and hence higher weight gains before and after weaning. Little is known about the effect of the age at which social housing begins. The aim of this study was to assess the effects of early versus late pairing on feeding behavior and weight gain before and after weaning. Holstein bull calves were reared individually (n=8 calves), or pair...

  3. Photoluminescence of ultra-high molecular weight polyethylene modified by fast atom bombardment

    Toth, S.; Fuele, M.; Veres, M.; Pocsik, I.; Koos, M.; Toth, A.; Ujvari, T.; Bertoti, I.

    2006-01-01

    An increase in the application potential of the ultra-high molecular weight polyethylene (UHMWPE) may be achieved by producing a hard, wear resistant carbonaceous modified surface layer on it. In this study the surface of UHMWPE samples was treated by 1 keV N, H and He fast atom bombardment (FAB) to obtain amorphous carbon surface layer which produces an enhancement of microhardness. The untreated and FAB-modified samples were investigated by photoluminescence, infrared, Raman and optical absorption spectroscopy. The FAB-treatment caused a nearly complete disappearance of the characteristic luminescence bands of UHMWPE (at 335, 351, 363 and 381 nm), the appearance of new bands at 459 and 495 nm due to the formation of new recombination levels in the FAB-treated samples. The remarkable decrease in integrated luminescence intensity indicates the appearance of new non-radiative recombination levels caused by FAB treatment. Structural modifications in FAB treated samples result in the development of structural arrangement containing sp 2 bonded carbon sites in rings or chains of different sizes and the electronic levels corresponding to these structural elements are situated in the forbidden gap in the electronic density of states which brings forth the observed changes of the photoluminescence properties

  4. Peptide and low molecular weight proteins based kidney targeted drug delivery systems.

    Xu, Pengfei; Zhang, Hailiang; Dang, Ruili; Jiang, Pei

    2018-05-30

    Renal disease is a worldwide public health problem, and unfortunately, the therapeutic index of regular drugs is limited. Thus, it is a great need to develop effective treatment strategies. Among the reported strategies, kidney-targeted drug delivery system is a promising method to increase renal efficacy and reduce extra-renal toxicity. In recent years, working as vehicles for targeted drug delivery, low molecular weight proteins (LMWP) and peptide have received immense attention due to their many advantages, such as selective accumulation in kidney, high drug loading capability, control over routes of biodegradation, convenience in modification at the amino terminus, and good biocompatibility. In this review, we describe the current LMWP and peptide carriers for kidney targeted drug delivery systems. In addition, we discuss different linking strategies between carriers and drugs. Furthermore, we briefly outline the current status and attempt to give an outlook on the further study. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  5. Synthesis of polymer gel electrolyte with high molecular weight poly(methyl methacrylate)-clay nanocomposite

    Meneghetti, Paulo; Qutubuddin, Syed; Webber, Andrew

    2004-01-01

    Polymer nanocomposite gel electrolytes consisting of high molecular weight poly(methyl methacrylate) PMMA-clay nanocomposite, ethylene carbonate (EC)/propylene carbonate (PC) as plasticizer, and LiClO 4 electrolyte are reported. Montmorillonite clay was ion exchanged with a zwitterionic surfactant (octadecyl dimethyl betaine) and dispersed in methyl methacrylate, which was then polymerized to synthesize PMMA-clay nanocomposites. The nanocomposite was dissolved in a mixture of EC/PC with LiClO 4 , heated and pressed to obtain polymer gel electrolyte. X-ray diffraction (XRD) of the gels indicated intercalated clay structure with d-spacings of 2.85 and 1.40 nm. In the gel containing plasticizer, the clay galleries shrink suggesting intercalation rather than partial exfoliation observed in the PMMA-clay nanocomposite. Ionic conductivity varied slightly and exhibited a maximum value of 8 x 10 -4 S/cm at clay content of 1.5 wt.%. The activation energy was determined by modeling the conductivity with a Vogel-Tamman-Fulcher expression. The clay layers are primarily trapped inside the polymer matrix. Consequently, the polymer does not interact significantly with LiClO 4 electrolyte as shown by FTIR. The presence of the clay increased the glass transition temperature (Tg) of the gel as determined by differential scanning calorimetry. The PMMA nanocomposite gel electrolyte shows a stable lithium interfacial resistance over time, which is a key factor for use in electrochemical applications

  6. Ancient low-molecular-weight organic acids in permafrost fuel rapid carbon dioxide production upon thaw.

    Drake, Travis W; Wickland, Kimberly P; Spencer, Robert G M; McKnight, Diane M; Striegl, Robert G

    2015-11-10

    Northern permafrost soils store a vast reservoir of carbon, nearly twice that of the present atmosphere. Current and projected climate warming threatens widespread thaw of these frozen, organic carbon (OC)-rich soils. Upon thaw, mobilized permafrost OC in dissolved and particulate forms can enter streams and rivers, which are important processors of OC and conduits for carbon dioxide (CO2) to the atmosphere. Here, we demonstrate that ancient dissolved organic carbon (DOC) leached from 35,800 y B.P. permafrost soils is rapidly mineralized to CO2. During 200-h experiments in a novel high-temporal-resolution bioreactor, DOC concentration decreased by an average of 53%, fueling a more than sevenfold increase in dissolved inorganic carbon (DIC) concentration. Eighty-seven percent of the DOC loss to microbial uptake was derived from the low-molecular-weight (LMW) organic acids acetate and butyrate. To our knowledge, our study is the first to directly quantify high CO2 production rates from permafrost-derived LMW DOC mineralization. The observed DOC loss rates are among the highest reported for permafrost carbon and demonstrate the potential importance of LMW DOC in driving the rapid metabolism of Pleistocene-age permafrost carbon upon thaw and the outgassing of CO2 to the atmosphere by soils and nearby inland waters.

  7. Ancient low–molecular-weight organic acids in permafrost fuel rapid carbon dioxide production upon thaw

    Drake, Travis W.; Wickland, Kimberly P.; Spencer, Robert G. M.; McKnight, Diane M.; Striegl, Robert G.

    2015-01-01

    Northern permafrost soils store a vast reservoir of carbon, nearly twice that of the present atmosphere. Current and projected climate warming threatens widespread thaw of these frozen, organic carbon (OC)-rich soils. Upon thaw, mobilized permafrost OC in dissolved and particulate forms can enter streams and rivers, which are important processors of OC and conduits for carbon dioxide (CO2) to the atmosphere. Here, we demonstrate that ancient dissolved organic carbon (DOC) leached from 35,800 y B.P. permafrost soils is rapidly mineralized to CO2. During 200-h experiments in a novel high–temporal-resolution bioreactor, DOC concentration decreased by an average of 53%, fueling a more than sevenfold increase in dissolved inorganic carbon (DIC) concentration. Eighty-seven percent of the DOC loss to microbial uptake was derived from the low–molecular-weight (LMW) organic acids acetate and butyrate. To our knowledge, our study is the first to directly quantify high CO2 production rates from permafrost-derived LMW DOC mineralization. The observed DOC loss rates are among the highest reported for permafrost carbon and demonstrate the potential importance of LMW DOC in driving the rapid metabolism of Pleistocene-age permafrost carbon upon thaw and the outgassing of CO2 to the atmosphere by soils and nearby inland waters.

  8. Studies on Antiviral and Immuno-Regulation Activity of Low Molecular Weight Fucoidan from Laminaria japonica

    Sun, Taohua; Zhang, Xinhui; Miao, Ying; Zhou, Yang; Shi, Jie; Yan, Meixing; Chen, Anjin

    2018-06-01

    The antiviral activity in vitro and in vivo and the effect of the immune system of two fucoidan fractions with low molecular weight and different sulfate content from Laminaria japonica (LMW fucoidans) were investigated in order to examine the possible mechanism. In vitro, I-type influenza virus, adenovirus and Parainfluenza virus I were used to infect Hep-2, Hela and MDCK cells, respectively. And 50% tissue culture infective dose was calculated to detect the antiviral activity of two LMW fucoidans. The results indicated that compared with the control group, 2 kinds of LMW fucoidans had remarkable antiviral activity in vitro in middle and high doses, while at low doses, the antiviral activity of 2 kinds of LMW fucoidans was not statistically different from that in the blank control group. And there was no statistically difference between two LMW fucoidans in antiviral activity. In vivo, LMW fucoidans could prolong the survival time of virus-infected mice, and could improve the lung index of virus-infected mice significantly, which have statistical differences with the control group significantly ( p 0.05). In this study, it was shown that both of two LMW fucoidans (LF1, LF2) could increase the thymus index, spleen index, phagocytic index, phagocytosis coefficient and half hemolysin value in middle and high doses, which suggested that LMW fucoidans could play an antiviral role by improving the quality of immune organs, improving immune cell phagocytosis and humoral immunity.

  9. Influences of poly (vinyl alcohol molecular weight and carbon nanotubes on radiation crosslinking shape memory polymers

    Aamer A.M. Alfayyadh

    2017-06-01

    Full Text Available Polyvinyl alcohol (PVA of two molecular weights was used to prepare shape memory polymers based on chemical-crosslinking by glutaraldehyde. The chemical-crosslinking was done in the presence of 2-carboxyethyl acrylate oligomers (CEA and nano-filler [multi-wall carbon nanotubes (MWCNT and functionalized carbon nanotubes (MWCNT-NH2] followed by radiation-induced crosslinking. The analysis of the material revealed an increase in the gel fraction and a significant reduction in swelling of the nanocomposite material that was crosslinked with both glutaraldehyde and ionizing radiation. The radiation crosslinked nanocomposites demonstrated approximately a 90% gelation over a range of 50–300 kGy irradiation doses. The scanning electron microscopy (SEM analysis showed a homogeneous distribution of nanocomposites in the composite matrix. The thermal properties of radiation crosslinked (PVA/CEA and (PVA-CEA-nano-fillers were investigated by a thermogravimetric analysis (TGA. The mechanical properties were examined via dynamic mechanical analysis (DMA which showed significant variation because of the addition of nanocomposites. This radiation crosslinked materials show good shape memory behavior that may be useful in many applications based on the range of temperatures at which Tan δ appears.

  10. Immune-enhancing activities of low molecular weight β-glucan depolymerized by gamma irradiation

    Sung, Nak-Yun; Byun, Eui-Hong; Kwon, Sun-Kyu; Song, Beom-Seok; Choi, Jong-il; Kim, Jae-Hun; Byun, Myung-Woo; Yoo, Young-Choon; Kim, Mee-Ree; Lee, Ju-Woon

    2009-07-01

    β-glucans are structural cell wall polymers of many microorganisms and cereals which possess immunomodulatory properties and have been used in the food, cosmetic and medical industry. In our previous study, β-glucan was depolymerized by gamma irradiation and leads to improve the solubility and viscosity. This study was carried out to evaluate the functional properties, mainly immune-enhancing activities of low molecular weight β-glucan fragmented by gamma irradiation. The results showed that RAW 264.7 macrophage cell stimulation activities of irradiated β-glucan were higher than that of non-irradiated β-glucan. In addition, the oral administration of gamma-irradiated β-glucan significantly increased the proliferation and cytokine (IFN-γ and IL-2) release of spleen and Peyer's patch cells compared with non-irradiated β-glucan. In conclusion, gamma irradiation could be used as an effective method for the production of depolymerized β-glucan improved functional property such as immunomodulatory activity.

  11. Immune-enhancing activities of low molecular weight β-glucan depolymerized by gamma irradiation

    Sung, Nak-Yun; Byun, Eui-Hong; Kwon, Sun-Kyu; Song, Beom-Seok; Choi, Jong-il; Kim, Jae-Hun; Byun, Myung-Woo; Yoo, Young-Choon; Kim, Mee-Ree; Lee, Ju-Woon

    2009-01-01

    β-glucans are structural cell wall polymers of many microorganisms and cereals which possess immunomodulatory properties and have been used in the food, cosmetic and medical industry. In our previous study, β-glucan was depolymerized by gamma irradiation and leads to improve the solubility and viscosity. This study was carried out to evaluate the functional properties, mainly immune-enhancing activities of low molecular weight β-glucan fragmented by gamma irradiation. The results showed that RAW 264.7 macrophage cell stimulation activities of irradiated β-glucan were higher than that of non-irradiated β-glucan. In addition, the oral administration of gamma-irradiated β-glucan significantly increased the proliferation and cytokine (IFN-γ and IL-2) release of spleen and Peyer's patch cells compared with non-irradiated β-glucan. In conclusion, gamma irradiation could be used as an effective method for the production of depolymerized β-glucan improved functional property such as immunomodulatory activity.

  12. Influence of different nominal molecular weight fractions of humic acids on phenol oxidation by permanganate.

    He, Di; Guan, Xiaohong; Ma, Jun; Yu, Min

    2009-11-01

    The effects of humic acid (HA) and its different nominal molecular weight (NMW) fractions on the phenol oxidation by permanganate were studied. Phenol oxidation by permanganate was enhanced by the presence of HA at pH 4-8, while slightly inhibited at pH 9-10. The effects of HA on phenol oxidation by permanganate were dependent on HA concentration and permanganate/phenol molar ratios. The high NMW fractions of HA enhanced phenol oxidation by permanganate at pH 7 more significantly than the low fractions of HA. The apparent second-order rate constants of phenol oxidation by permanganate in the presence of HA correlated well with their specific ultraviolet absorption (SUVA) at 254 nm and specific violet absorption (SVA) at 465 or 665 nm. High positive correlation coefficients (R(2) > 0.72) implied that pi-electrons of HA strongly influenced the reactivity of phenol towards permanganate oxidation which agreed well with the information provided by fluorescence spectroscopy. The FTIR analysis indicated that the HA fractions rich in aliphatic character, polysaccharide-like substances, and the amount of carboxylate groups had less effect on phenol oxidation by permanganate. The negative correlation between the rate constants of phenol oxidation by permanganate and O/C ratios suggested that the oxidation of phenol increased with a decrease in the content of oxygen-containing functional groups.

  13. The effects of polymer molecular weight on filament thinning and drop breakup in microchannels

    Arratia, P E; Cramer, L-A; Gollub, J P; Durian, D J

    2009-01-01

    We investigate the effects of fluid elasticity on the dynamics of filament thinning and drop breakup processes in a cross-slot microchannel. Elasticity effects are examined using dilute aqueous polymeric solutions of molecular weight (MW) ranging from 1.5x10 3 to 1.8x10 7 . Results for polymeric fluids are compared to those for a viscous Newtonian fluid. The shearing or continuous phase that induces breakup is mineral oil. All fluids possess similar shear-viscosity (∼0.2 Pa s) so that the viscosity ratio between the oil and aqueous phases is close to unity. Measurements of filament thickness as a function of time show different thinning behavior for the different aqueous fluids. For Newtonian fluids, the thinning process shows a single exponential decay of the filament thickness. For low MW fluids (10 3 , 10 4 and 10 5 ), the thinning process also shows a single exponential decay, but with a decay rate that is slower than for the Newtonian fluid. The decay time increases with polymer MW. For high MW (10 6 and 10 7 ) fluids, the initial exponential decay crosses over to a second exponential decay in which elastic stresses are important. We show that the decay rate of the filament thickness in this exponential decay regime can be used to measure the steady extensional viscosity of the fluids. At late times, all fluids cross over to an algebraic decay which is driven mainly by surface tension.

  14. Extrudable polymer-polymer composites based on ultra-high molecular weight polyethylene

    Panin, S. V.; Kornienko, L. A.; Alexenko, V. O.; Buslovich, D. G.; Dontsov, Yu. V.

    2017-12-01

    Mechanical and tribotechnical characteristics of polymer-polymeric composites of UHMWPE are studied with the aim of developing extrudable, wear-resistant, self-lubricant polymer mixtures for Additive Manufacturing (AM). The motivation of the study is their further application as feedstocks for 3D printing. Blends of UHMWPE with graft- and block copolymers of low-density polyethylene (HDPE-g-VTMS, HDPE-g-SMA, HDPE-b-EVA), polypropylene (PP), block copolymers of polypropylene and polyamide with linear low density polyethylene (PP-b-LLDPE, PA-b-LLDPE), as well as cross-linked polyethylene (PEX-b), are examined. The choice of compatible polymer components for an ultra- high molecular weight matrix for increasing processability (extrudability) is motivated by the search for commercially available and efficient additives aimed at developing wear-resistant extrudable polymer composites for additive manufacturing. The extrudability, mechanical properties and wear resistance of UHMWPE-based polymer-polymeric composites under sliding friction with different velocities and loads are studied.

  15. Contribution of low molecular weight phenols to bitter taste and mouthfeel properties in red wines.

    Gonzalo-Diago, Ana; Dizy, Marta; Fernández-Zurbano, Purificación

    2014-07-01

    The aim of this study was to explore the relationship between low molecular weight compounds present in wines and their sensory contribution. Six young red wines were fractionated by gel permeation chromatography and subsequently each fraction obtained was separated from sugars and acids by solid phase extraction. Wines and both fractions were in-mouth evaluated by a trained sensory panel and UPLC-MS analyses were performed. The lack of ethanol and proanthocyanidins greatly increased the acidity perceived. The elimination of organic acids enabled the description of the samples, which were evaluated as bitter, persistent and slightly astringent. Coutaric acid and quercetin-3-O-rutinoside appear to be relevant astringent compounds in the absence of proanthocyanidins. Bitter taste was highly correlated with the in-mouth persistence. A significant predictive model for bitter taste was built by means of PLSR. Further research must be carried out to validate the sensory contribution of the compounds involved in bitterness and astringency and to verify the sensory interactions observed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Role of redox environment on the oligomerization of higher molecular weight adiponectin

    Nuñez Martha

    2011-05-01

    Full Text Available Abstract Background Adiponectin is an adipocyte-secreted hormone with insulin-sensitizing and anti-inflammatory actions. The assembly of trimeric, hexameric, and higher molecular weight (HMW species of adiponectin is a topic of significant interest because physiological actions of adiponectin are oligomer-specific. In addition, adiponectin assembly is an example of oxidative oligomerization of multi-subunit protein complexes in endoplasmic reticulum (ER. Results We previously reported that trimers assemble into HMW adiponectin via intermediates stabilized by disulfide bonds, and complete oxidation of available cysteines locks adiponectin in hexameric conformation. In this study, we examined the effects of redox environment on the rate of oligomer formation and the distribution of oligomers. Reassembly of adiponectin under oxidizing conditions accelerated disulfide bonding but favored formation of hexamers over the HMW species. Increased ratios of HMW to hexameric adiponectin could be achieved rapidly under oxidizing conditions by promoting disulfide rearrangement. Conclusions Based upon these observations, we propose oxidative assembly of multi-subunit adiponectin complexes in a defined and stable redox environment is favored under oxidizing conditions coupled with high rates of disulfide rearrangement.

  17. Lack of Substantial Post-Cessation Weight Increase in Electronic Cigarettes Users

    Cristina Russo

    2018-03-01

    Full Text Available Minimization of post-cessation weight gain in quitters is important, but existing approaches (e.g., antismoking medications shows only limited success. We investigated changes in body weight in smokers who quit or reduced substantially their cigarette consumption by switching to electronic cigarettes (ECs use. Body weight and smoking/vaping history were extracted from medical records of smokers and ex-smokers to match three study groups: (1 regular EC users on at least two consecutive follow-up visits; (2 regular smokers (and not using ECs; (3 subjects who reported sustained smoking abstinence after completing a cessation program. Review of their medical records was conducted at two follow-up visits at 6- (F/U 6m and 12-months (F/U 12m. A total of 86 EC users, 93 regular smokers, and 44 quitters were studied. In the EC users study group, cigarettes/day use decreased from 21.1 at baseline to 1.8 at F/U 12m (p < 0.0001. Dual usage was reported by approximately 50% of EC users. Both within factor (time, p < 0.0001 and between factor (study groups, p < 0.0001 produced significant effect on weight (% change from baseline, with a significant 4.8% weight gain from baseline in the quitters study group at F/U 12m. For the EC users, weight gain at F/U 12m was only 1.5% of baseline. There was no evidence of post-cessation weight increase in those who reduced substantially cigarette consumption by switching to ECs (i.e., dual users and only modest post-cessation weight increase was reported in exclusive EC users at F/U 12m. By reducing weight gain and tobacco consumption, EC-based interventions may promote an overall improvement in quality of life.

  18. Role of Laccase and Low Molecular Weight Metabolites from Trametes versicolor in Dye Decolorization

    Diego Moldes

    2012-01-01

    Full Text Available The studies regarding decolorization of dyes by laccase may not only inform about the possible application of this enzyme for environmental purposes, but also may provide important information about its reaction mechanism and the influence of several factors that could be involved. In this paper, decolorization of crystal violet and phenol red was carried out with different fractions of extracellular liquids from Trametes versicolor cultures, in order to describe the role of laccase in this reaction. Moreover, the possible role of the low molecular weight metabolites (LMWMs also produced by the fungus was evaluated. The results confirm the existence of a nonenzymatic decolorization factor, since the nonprotein fraction of the extracellular liquids from cultures of T. versicolor has shown decolorization capability. Several experiments were performed in order to identify the main compounds related to this ability, which are probably low molecular weight peroxide compounds.

  19. Managing cancer-related venous thromboembolic disease: low-molecular-weight heparins and beyond.

    O'Connell, Casey L; Liebman, Howard A

    2008-12-01

    Venous thromboembolism is a major contributor to the morbidity and mortality of patients with cancer. For patients undergoing cancer surgery, several trials support the safety and efficacy of unfractionated heparin and of low-molecular-weight heparin for the prevention of venous thromboembolism, while data regarding the efficacy and safety of these agents in the setting of medical hospitalization is less definitive and must be extracted from trials including noncancer patients with different thrombotic risk factors. Randomized clinical studies confirm that patients with cancer who develop venous thromboembolism have superior outcomes when treated with long-term low-molecular-weight heparin as compared with warfarin. Novel anticoagulants that are orally bioavailable and function by directly inhibiting factor Xa or thrombin are entering the market. To date, data regarding the efficacy and safety of these novel anticoagulants as venous thromboembolism prophylaxis and treatment in cancer patients are not available and must be extracted from larger trials with heterogeneous patient populations.

  20. Participation of Low Molecular Weight Electron Carriers in Oxidative Protein Folding

    József Mandl

    2009-03-01

    Full Text Available Oxidative protein folding is mediated by a proteinaceous electron relay system, in which the concerted action of protein disulfide isomerase and Ero1 delivers the electrons from thiol groups to the final acceptor. Oxygen appears to be the final oxidant in aerobic living organisms, although the existence of alternative electron acceptors, e.g. fumarate or nitrate, cannot be excluded. Whilst the protein components of the system are well-known, less attention has been turned to the role of low molecular weight electron carriers in the process. The function of ascorbate, tocopherol and vitamin K has been raised recently. In vitro and in vivo evidence suggests that these redox-active compounds can contribute to the functioning of oxidative folding. This review focuses on the participation of small molecular weight redox compounds in oxidative protein folding.

  1. Simulated dynamic response of a multi-stage compressor with variable molecular weight flow medium

    Babcock, Dale A.

    1995-01-01

    A mathematical model of a multi-stage compressor with variable molecular weight flow medium is derived. The modeled system consists of a five stage, six cylinder, double acting, piston type compressor. Each stage is followed by a water cooled heat exchanger which serves to transfer the heat of compression from the gas. A high molecular weight gas (CFC-12) mixed with air in varying proportions is introduced to the suction of the compressor. Condensation of the heavy gas may occur in the upper stage heat exchangers. The state equations for the system are integrated using the Advanced Continuous Simulation Language (ACSL) for determining the system's dynamic and steady state characteristics under varying operating conditions.

  2. Preparation of the low molecular weight serum proteome for mass spectrometry analysis.

    Waybright, Timothy J; Chan, King C; Veenstra, Timothy D; Xiao, Zhen

    2013-01-01

    The discovery of viable biomarkers or indicators of disease states is complicated by the inherent complexity of the chosen biological specimen. Every sample, whether it is serum, plasma, urine, tissue, cells, or a host of others, contains thousands of large and small components, each interacting in multiple ways. The need to concentrate on a group of these components to narrow the focus on a potential biomarker candidate becomes, out of necessity, a priority, especially in the search for immune-related low molecular weight serum biomarkers. One such method in the field of proteomics is to divide the sample proteome into groups based on the size of the protein, analyze each group, and mine the data for statistically significant items. This chapter details a portion of this method, concentrating on a method for fractionating and analyzing the low molecular weight proteome of human serum.

  3. Chemical modification of high molecular weight polyethylene through gamma radiation for biomaterials applications

    Raposo, Matheus P.; Rocha, Marisa C.G.

    2015-01-01

    Ultra high molecular weight polyethylene has been used in the medical field due to its high mechanical properties compared to the other polymers. Its main application is in the development of orthopedic implants, which requires high resistance to abrasion. One of the most used methods is the introduction of crosslinks in the polymer through gamma irradiation. In order to prevent oxidation reactions, studies have been developed using tacoferol (vitamin E) as an antioxidant for the material. The ascorbic acid (vitamin C), however, has been appointed as a viable alternative for vitamin E. In this work, a high molecular weight polyethylene grade (HMWPE) and polyethylene samples formulated with vitamin C were submitted to gamma radiation. Thermodynamic-mechanical methods and gel content determinations were used to characterize the samples obtained. The sample containing 1% of vitamin C and irradiated with 50 KGy of gamma radiation presented the highest content of crosslinks. (author)

  4. High molecular weight DNA assembly in vivo for synthetic biology applications.

    Juhas, Mario; Ajioka, James W

    2017-05-01

    DNA assembly is the key technology of the emerging interdisciplinary field of synthetic biology. While the assembly of smaller DNA fragments is usually performed in vitro, high molecular weight DNA molecules are assembled in vivo via homologous recombination in the host cell. Escherichia coli, Bacillus subtilis and Saccharomyces cerevisiae are the main hosts used for DNA assembly in vivo. Progress in DNA assembly over the last few years has paved the way for the construction of whole genomes. This review provides an update on recent synthetic biology advances with particular emphasis on high molecular weight DNA assembly in vivo in E. coli, B. subtilis and S. cerevisiae. Special attention is paid to the assembly of whole genomes, such as those of the first synthetic cell, synthetic yeast and minimal genomes.

  5. Isolation of low-molecular-weight lead-binding protein from human erythrocytes

    Raghavan, S.R.V.; Gonick, H.C.

    1977-01-01

    In blood, lead is mainly associated with erythrocytes and only a very small amount is found in plasma. Previously it was thought that the lead was bound to the erythrocyte cell membrane but more recently it has been observed that lead is bound primarily to the cell contents, ostensibly hemoglobin. In examining the lead-binding properties of normal human erythrocytes and those of lead-exposed industrial workers, we have found that, whereas lead binds only to hemoglobin in normal erythrocytes, there is also appreciable binding of lead to a low-molecular weight-protein in erythrocytes from lead-exposed workers. The synthesis of this protein may be induced by lead exposure. The 10,000 molecular weight protein may act as a storage site and mechanism for segregating lead in a non-toxic form

  6. Use of electroporation for high-molecular-weight DNA-mediated gene transfer.

    Jastreboff, M M; Ito, E; Bertino, J R; Narayanan, R

    1987-08-01

    Electroporation was used to introduce high-molecular-weight DNA into murine hematopoietic cells and NIH3T3 cells. CCRF-CEM cells were stably transfected with SV2NEO plasmid and the genomic DNA from G-418-resistant clones (greater than 65 kb) was introduced into mouse bone marrow and NIH3T3 cells by electroporation. NEO sequences and expression were detected in the hematopoietic tissues of lethally irradiated mice, with 24% of individual spleen colonies expressing NEO. The frequency of genomic DNA transfer into NIH3T3 cells was 0.25 X 10(-3). Electroporation thus offers a powerful mode of gene transfer not only of cloned genes but also of high-molecular-weight DNA into cells.

  7. Evaluation of environmental degradation effects in morphology of ultra-high molecular weight polyethylene (UHMWPE) fibers

    Vivas, Viviane; Zylberberg, Marcel P.; Cardoso, Andre Luis V.; Pereira, Iaci M.; Weber, Ricardo P.; Suarez, Joao C. Miguez

    2015-01-01

    This study aims to evaluate changes in the morphology of ultra-high molecular weight polyethylene fiber (UHMWPE), before and after exposure to environmental agents. Fibers produced by two different manufacturers were analyzed. To characterize the morphology, we used the technique of small angle x-ray scattering (SAXS). The results demonstrate that the original morphology of the fibers was UHMWPE affected by the defects caused by exposure to environmental agents. (author)

  8. A Simple Thermoplastic Substrate Containing Hierarchical Silica Lamellae for High-Molecular-Weight DNA Extraction.

    Zhang, Ye; Zhang, Yi; Burke, Jeffrey M; Gleitsman, Kristin; Friedrich, Sarah M; Liu, Kelvin J; Wang, Tza-Huei

    2016-12-01

    An inexpensive, magnetic thermoplastic nanomaterial is developed utilizing a hierarchical layering of micro- and nanoscale silica lamellae to create a high-surface-area and low-shear substrate capable of capturing vast amounts of ultrahigh-molecular-weight DNA. Extraction is performed via a simple 45 min process and is capable of achieving binding capacities up to 1 000 000 times greater than silica microparticles. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Silver Nanoparticles Modification of Ultra High Molecular Weight Polyethylene in Non-Aqueous Medium

    V. N. Glushko; L. I. Blokhina; E. E. Anisimova; M. V. Bogdanovskaya; V. I. Kozhukhov; T. A. Cherdyntseva

    2016-01-01

    A series of experiments for obtaining modified with silver nanoparticles ultra-high molecular weight polyethylene (UHMWPE) is done. Optimal precursors are silver trifluoroacetate, silver nitrate and silver methanesulfonate. Three variants of UHMWPE modification is studied: 1) the polyol synthesis, 2) polymer processing silver nanoparticle colloid and 3) reduction of silver salt solution in the UHMWPE polymer matrix. It is found that the last method is optimal. The specific surface of obtained...

  10. A low molecular weight urinary proteome profile of human kidney aging

    Zürbig, Petra; Decramer, Stéphane; Dakna, Mohammed; Jantos, Justyna; Good, David M.; Coon, Joshua J.; Bandin, Flavio; Mischak, Harald; Bascands, Jean-Loup; Schanstra, Joost P

    2009-01-01

    Aging induces morphological changes of the kidney and reduces renal function. We analyzed the low molecular weight urinary proteome of 324 healthy individuals from 2-73 years of age to gain insight on renal aging in humans. We observed age-related modification of secretion of 325 out of 5000 urinary peptides. The majority of these changes was associated with renal development before and during puberty, while 49 peptides were related to aging in adults. Of these 49 peptides, the majority were ...

  11. Growth of thin films of low molecular weight proteins by matrix assisted pulsed laser evaporation (MAPLE)

    Matei, Andreea; Schou, Jørgen; Constantinescu, C.

    2011-01-01

    Thin films of lysozyme and myoglobin grown by matrix assisted pulsed laser evaporation (MAPLE) from a water ice matrix have been investigated. The deposition rate of these two low molecular weight proteins (lysozyme: 14307 amu and myoglobin: 17083 amu) exhibits a maximum of about 1–2 ng/cm2 per....... The results for lysozyme demonstrate that the fragmentation rate of the proteins during the MAPLE process is not influenced by the pH of the water solution prior to freezing....

  12. Study the Effect of Imposing Surfactants toward the Evaporation of Low Molecular Weight Alcohol

    Mohammad , H.H.; Sharifuddin Md. , Zain; Rashid Atta , Khan; Khalisanni , Khalid

    2013-01-01

    International audience; In this paper, Reversed-Flow Gas Chromatography (RF-GC) is utilized to investigate the evaporation of low molecular weight alcohol. Evaporation rates as well as the diffusion rates of methanol are determined with a surfactant monolayer on the surface of the liquid; while nitrogen acts as carrier gas, at 313 K. The precision (>99.9%) and accuracy of this investigation demonstrates the potential of current methodologies for environmental impact studies; this is further v...

  13. Study the Effect of Imposing Surfactants toward the Evaporation of Low Molecular Weight Alcohol

    H.H., Mohammad; Zain, Sharifuddin Mohd; Khan, Rashid Atta; Khalid, Khalisanni

    2017-01-01

    In this paper, Reversed-Flow Gas Chromatography (RF-GC) is utilized to investigate the evaporation of low molecular weight alcohol. Evaporation rates as well as the diffusion rates of methanol are determined with a surfactant monolayer on the surface of the liquid; while nitrogen acts as carrier gas, at 313 K. The precision (>99.9%) and accuracy of this investigation demonstrates the potential of current methodologies for environmental impact studies; this is further verified when the results...

  14. Bilateral rectal sheath hematomas after low-molecular weight heparin treatment in uremia.

    Xu, Lu; Liu, Lei; Li, Xinjian

    2017-11-01

    Rectus sheath hematomas (RSHs) are uncommon. They are usually unilateral and rarely bilateral. In this paper, we report the first case of spontaneous bilateral RSHs in a uremic patient after the administration of the first dose of low-molecular weight heparin during hemodialysis. The most interesting aspect of this case is that the main symptom of RSH in our patient was urinary bladder irritation. We highlight the importance of the prompt diagnosis and management of this medical emergency.

  15. Proton transport properties of poly(aspartic acid) with different average molecular weights

    Nagao, Yuki, E-mail: ynagao@kuchem.kyoto-u.ac.j [Department of Mechanical Systems and Design, Graduate School of Engineering, Tohoku University, 6-6-01 Aoba Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Imai, Yuzuru [Institute of Development, Aging and Cancer (IDAC), Tohoku University, 4-1 Seiryo-cho, Aoba-ku, Sendai 980-8575 (Japan); Matsui, Jun [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 2-1-1 Katahira, Sendai 980-8577 (Japan); Ogawa, Tomoyuki [Department of Electronic Engineering, Graduate School of Engineering, Tohoku University, 6-6-05 Aoba Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Miyashita, Tokuji [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 2-1-1 Katahira, Sendai 980-8577 (Japan)

    2011-04-15

    Research highlights: Seven polymers with different average molecular weights were synthesized. The proton conductivity depended on the number-average degree of polymerization. The difference of the proton conductivities was more than one order of magnitude. The number-average molecular weight contributed to the stability of the polymer. - Abstract: We synthesized seven partially protonated poly(aspartic acids)/sodium polyaspartates (P-Asp) with different average molecular weights to study their proton transport properties. The number-average degree of polymerization (DP) for each P-Asp was 30 (P-Asp30), 115 (P-Asp115), 140 (P-Asp140), 160 (P-Asp160), 185 (P-Asp185), 205 (P-Asp205), and 250 (P-Asp250). The proton conductivity depended on the number-average DP. The maximum and minimum proton conductivities under a relative humidity of 70% and 298 K were 1.7 . 10{sup -3} S cm{sup -1} (P-Asp140) and 4.6 . 10{sup -4} S cm{sup -1} (P-Asp250), respectively. Differential thermogravimetric analysis (TG-DTA) was carried out for each P-Asp. The results were classified into two categories. One exhibited two endothermic peaks between t = (270 and 300) {sup o}C, the other exhibited only one peak. The P-Asp group with two endothermic peaks exhibited high proton conductivity. The high proton conductivity is related to the stability of the polymer. The number-average molecular weight also contributed to the stability of the polymer.

  16. Hypoglycemic effect of polysaccharides with different molecular weight of Pseudostellaria heterophylla

    2013-01-01

    Abstracts Background The aims of this study were to evaluate the antidiabetic activity and to detect molecular size of Pseudostellaria heterophylla polysaccharide (PHP). Pseudostellaria heterophylla is a medicine extensively used in traditional Chinese medicine formulas to treat diabetes and its complications. Methods Molecular weight of PHP was determined by gel permeation chromatography combined with phenol-sulphuric acid method and the monosaccharides composition was determined by HPLC with a precolumn derivatization. Four polysaccharides with different molecular weight were compared for hypoglycemic active on two animal models both high does alloxan induced type1 diabetic mellitus (T1DM) and high-fat/lower does streptozotocin induced type2 diabetic mellitus (T2DM). Blood sugar, glucose tolerance, and insulin tolerance were detected. Rat serum IL-1β, IL-2, IL-10, Leptin, TNF-α, Acrp30 and CRP were also analyzed by sandwich-ELISA approaches to preliminary probe the hypoglycemic mechanism of PHP. Results The hypoglycemic effects related to molecular size of polysaccharide were more effective against T2DM than T1DM. PHP comprise four monosaccharides of galacturonic acid, glucose, galactose and arabinos. T2DM rats daily receiving oral dose of polysaccharide(100 ~ 400 mg/kg) with 50 ~ 210 kDa molecular weight (PF40) could not only significantly lower blood sugar but also reduce total triglyceride level in serum. PF40 improves in insulin tolerance inhibited the expression of some biomarkers including inflammatory cytokine TNF-α and elevated anti-inflammatory cytokine IL-10, regulated adiponectin Acrp30 and leptin. Conclusions PF40 prevent the cascade of inflammatory events in the treatment of T2DM to block overweight progresses to obesity. PMID:24131482

  17. Update on the clinical use of the low-molecular-weight heparin, parnaparin

    Giuseppe Camporese

    2009-09-01

    Full Text Available Giuseppe Camporese1, Enrico Bernardi2, Franco Noventa31Unit of Angiology and 3Department of Clinical and Experimental Medicine, Clinical Epidemiology Group, University Hospital of Padua, Italy; 2Department of Emergency and Accident Medicine, Hospital of Conegliano Veneto, ItalyAbstract: Parnaparin is a low-molecular-weight heparin that has widely shown its efficacy and safety in prevention of venous thromboembolism, in the treatment of chronic venous disorders, and in the treatment of venous and arterial (stable and unstable angina, acute ST-segment elevation myocardial infarction thrombosis. Parnaparin at the respective dosages of 3200, 4250, 6400, or 12800 IUaXa for a period ranging from 3 to 5 days to 6 months, is usually administered subcutaneously by means of once-daily regimen and is better tolerated than unfractionated heparin at the injection site. In the variety of commercially available low-molecular-weight heparins, parnaparin represents a useful therapeutic option, even though little evidence is available comparing the superiority or the equivalent efficacy and safety of parnaparin to that of the unfractionated heparin or placebo. This review summarizes the available literature on the use of parnaparin in different settings of cardiovascular diseases, including papers published during the past year and ongoing studies.Keywords: low-molecular-weight heparin, heparin, parnaparin, acute coronary syndromes, venous thromboembolism

  18. Developmental co-expression of small molecular weight apolipoprotein B synthesis and triacylglycerol secretion

    Coleman, R.A.; Haynes, E.B.; Sand, T.M.; Davis, R.A.

    1987-01-01

    The development of the liver's ability to coordinately express the synthesis and secretion of the two major components of very low density lipoproteins (VLDL): triacylglycerol (TG) and apolipoprotein B (apo B) was examined in cultured hepatocytes obtained from fetal, suckling and adult rats. Hepatocytes from fetal and suckling rats synthesized and secreted TG at rates lower than that displayed by adult cells. When TG synthesis was equalized by adding oleic acid to the culture medium, fetal cells still secreted only 39% as much TG as did adult cells. To determine the basis for the apparent defect in VLDL assembly/secretion displayed by fetal cells, the synthesis and secretion of [ 35 S]methionine-labeled apo B was quantified by immunoprecipitation. Although adult and fetal cells synthesized and secreted large molecular weight apo B at similar rates, the synthesis and secretion of small molecular weight apo B was 2-fold greater in adult cells. These data suggest that the ability to assemble/secrete VLDL triacylglycerol varies in parallel with the developmental expression of small molecular weight apo B. Furthermore, these studies show the usefulness of the cultured rat hepatocyte model for examining the ontogeny and regulation of VLDL assembly/secretion

  19. Temperature dependence of viscoelasticity of crystalline cellulose with different molecular weights added to silicone elastomer

    Sugino, Naoto; Nakajima, Shinya; Kameda, Takao; Takei, Satoshi; Hanabata, Makoto

    2017-08-01

    Silicone elastomers ( polydimethylsiloxane _ PDMS) are widely used in the field of imprint lithography and microcontactprinting (μCP). When performing microcontactprinting, the mechanical properties of the PCMS as a base material have a great influence on the performance of the device. Cellulose nanofibers having features of high strength, high elasticity and low coefficient of linear expansion have attracted attention in recent years due to their characteristics. Therefore, three types of crystalline cellulose having different molecular weights were added to PDMS to prepare a composite material, and dynamic viscoelasticity was measured using a rheometer. The PDMS with the highest molecular weight crystalline cellulose added exhibited smaller storage modulus than PDMS with other molecular weight added in all temperature ranges. Furthermore, when comparing PDMS to which crystalline cellulose was added and PDMS which is not added, the storage modulus of PDMS to which cellulose was added in the low temperature region was higher than that of PDMS to which it was not added, but it was reversed in the high temperature region It was a result. When used in a low temperature range (less than 150 ° C.), it can be said that cellulose can function as a reinforcing material for PDMS.

  20. Increase in Complexity and Information through Molecular Evolution

    Peter Schuster

    2016-11-01

    survival through sufficiently high mutation rates is observed. The evolutionary processes in the model are accompanied by gains in information on the environment of the evolving populations. In order to provide a useful basis for comparison, two forms of information, syntactic or Shannon information and semantic information are introduced here. Both forms of information are defined for simple evolving systems at the molecular level. Selection leads primarily to an increase in semantic information in the sense that higher fitness allows for more efficient exploitation of the environment and provides the basis for more progeny whereas understanding transitions involves characteristic contributions from both Shannon information and semantic information.

  1. Increased pericarp cell length underlies a major quantitative trait locus for grain weight in hexaploid wheat.

    Brinton, Jemima; Simmonds, James; Minter, Francesca; Leverington-Waite, Michelle; Snape, John; Uauy, Cristobal

    2017-08-01

    Crop yields must increase to address food insecurity. Grain weight, determined by grain length and width, is an important yield component, but our understanding of the underlying genes and mechanisms is limited. We used genetic mapping and near isogenic lines (NILs) to identify, validate and fine-map a major quantitative trait locus (QTL) on wheat chromosome 5A associated with grain weight. Detailed phenotypic characterisation of developing and mature grains from the NILs was performed. We identified a stable and robust QTL associated with a 6.9% increase in grain weight. The positive interval leads to 4.0% longer grains, with differences first visible 12 d after fertilization. This grain length effect was fine-mapped to a 4.3 cM interval. The locus also has a pleiotropic effect on grain width (1.5%) during late grain development that determines the relative magnitude of the grain weight increase. Positive NILs have increased maternal pericarp cell length, an effect which is independent of absolute grain length. These results provide direct genetic evidence that pericarp cell length affects final grain size and weight in polyploid wheat. We propose that combining genes that control distinct biological mechanisms, such as cell expansion and proliferation, will enhance crop yields. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  2. High Birth Weight Increases the Risk for Bone Tumor: A Systematic Review and Meta-Analysis

    Songfeng Chen

    2015-09-01

    Full Text Available There have been several epidemiologic studies on the relationship between high birth weight and the risk for bone tumor in the past decades. However, due to the rarity of bone tumors, the sample size of individual studies was generally too small for reliable conclusions. Therefore, we have performed a meta-analysis to pool all published data on electronic databases with the purpose to clarify the potential relationship. According to the inclusion and exclusion criteria, 18 independent studies with more than 2796 cases were included. As a result, high birth weight was found to increase the risk for bone tumor with an Odds Ratio (OR of 1.13, with the 95% confidence interval (95% CI ranging from 1.01 to 1.27. The OR of bone tumor for an increase of 500 gram of birth weight was 1.01 (95% CI 1.00–1.02; p = 0.048 for linear trend. Interestingly, individuals with high birth weight had a greater risk for osteosarcoma (OR = 1.22, 95% CI 1.06–1.40, p = 0.006 than those with normal birth weight. In addition, in the subgroup analysis by geographical region, elevated risk was detected among Europeans (OR = 1.14, 95% CI 1.00–1.29, p = 0.049. The present meta-analysis supported a positive association between high birth weight and bone tumor risk.

  3. Can exercise increase fitness and reduce weight in patients with schizophrenia and depression?

    Krogh, Jesper; Speyer, Helene; Nørgaard, Hans Christian Brix

    2014-01-01

    in this patient group and low levels of physical activity is associated with increased risk of cardiovascular disease, diabetes, and all-cause mortality. This study aimed to review trials allocating patients with either schizophrenia or depression to exercise interventions for effect on cardiovascular fitness......, strength, and weight. METHODS: We searched PubMed, Embase, and PsycINFO including randomized clinical trial allocating patients with either schizophrenia or depression to isolated exercise interventions. RESULTS: We identified five trials including patients with schizophrenia (n = 94) and found little...... evidence that exercise could increase cardiovascular fitness or decrease weight. Nine exercise trials for patients with depression (n = 892) were identified increasing cardiovascular fitness by 11-30% and strength by 33-37%. No evidence in favor of exercise for weight reduction was found. CONCLUSION: Based...

  4. Increased post-operative cardiopulmonary fitness in gastric bypass patients is explained by weight loss

    Lund, M. T.; Hansen, M.; Wimmelmann, C. L.

    2016-01-01

    Roux-en-Y gastric bypass (RYGB) leads to a major weight loss in obese patients. However, given that most patients remain obese after the weight loss, regular exercise should be part of a healthier lifestyle. The primary aim of this study was to investigate the cardiopulmonary fitness in obese...... ± 2 kg during the study period. VO2max increased (A: 21 ± 1 vs D: 29 mL/min/kg, P exercise decreased and self......-perceived physical fitness increased after RYGB. Self-reported low- and high-intensity physical activity did not change. With weight loss, self-rated fitness level increased and the limitations to perform exercise decreased in RYGB patients. Nevertheless, as shown by the lower absolute VO2max, RYGB patients do...

  5. Do E-cigarettes induce weight changes and increase cardiometabolic risk? A signal for the future.

    Verhaegen, A; Van Gaal, L

    2017-10-01

    The prevalence of non-cigarette tobacco use in electronic cigarettes, also called vaping, is rapidly increasing, especially in adolescents and young adults, due to attractive marketing techniques promoting them as healthier alternatives to conventional tobacco cigarettes. Although smoking is associated with weight loss, it increases insulin resistance and attributes to other features of the metabolic syndrome, increasing the cardiometabolic risk profile. Whether vaping has the same deleterious effects on metabolic parameters as regular cigarette smoke has not yet been studied thoroughly in humans. However, animal model experiments attribute comparable effects of e-cigarette smoking, even without nicotine exposure, on weight and metabolic parameters as compared to smoking cigarettes. In this review paper, we want to give an overview of published data on the effects on weight and cardiometabolic parameters of e-cigarette use and formulate some mechanistic hypotheses. © 2017 World Obesity Federation.

  6. Developing a Macroscopic Mechanistic Model for Low Molecular Weight Diffusion through Polymers in the Rubbery State

    Martinez-Lopez, Brais; Huguet, P.; Gontard, N.

    2016-01-01

    Raman microspectroscopy was used to determine the Fickian diffusivity of two families of low molecular weight molecules through amorphous polystyrene in the rubbery state. Different effects of the temperature on diffusivity for each of the families suggested that molecular mobility is controlled...... by both the volume and flexibility of the diffusing substance when the movement of polymer chains can generate stress induced deformation of molecules. The diffusing molecules were represented as Newtonian spring–bead systems, which allowed us to quantify their flexibility, in function of the vibration...... frequency of their bonds by reconstructing their theoretical spectra. Results showed that the use of molecular descriptors that take into account flexibility rather than the most stable conformation of the diffusing molecules may improve the description of the diffusion behavior caused by variations...

  7. Skeletal stiffening in an amphibious fish out of water is a response to increased body weight.

    Turko, Andy J; Kültz, Dietmar; Fudge, Douglas; Croll, Roger P; Smith, Frank M; Stoyek, Matthew R; Wright, Patricia A

    2017-10-15

    Terrestrial animals must support their bodies against gravity, while aquatic animals are effectively weightless because of buoyant support from water. Given this evolutionary history of minimal gravitational loading of fishes in water, it has been hypothesized that weight-responsive musculoskeletal systems evolved during the tetrapod invasion of land and are thus absent in fishes. Amphibious fishes, however, experience increased effective weight when out of water - are these fishes responsive to gravitational loading? Contrary to the tetrapod-origin hypothesis, we found that terrestrial acclimation reversibly increased gill arch stiffness (∼60% increase) in the amphibious fish Kryptolebias marmoratus when loaded normally by gravity, but not under simulated microgravity. Quantitative proteomics analysis revealed that this change in mechanical properties occurred via increased abundance of proteins responsible for bone mineralization in other fishes as well as in tetrapods. Type X collagen, associated with endochondral bone growth, increased in abundance almost ninefold after terrestrial acclimation. Collagen isoforms known to promote extracellular matrix cross-linking and cause tissue stiffening, such as types IX and XII collagen, also increased in abundance. Finally, more densely packed collagen fibrils in both gill arches and filaments were observed microscopically in terrestrially acclimated fish. Our results demonstrate that the mechanical properties of the fish musculoskeletal system can be fine-tuned in response to changes in effective body weight using biochemical pathways similar to those in mammals, suggesting that weight sensing is an ancestral vertebrate trait rather than a tetrapod innovation. © 2017. Published by The Company of Biologists Ltd.

  8. An interaction between NDE1 and high birth weight increases schizophrenia susceptibility.

    Wegelius, Asko; Pankakoski, Maiju; Tomppo, Liisa; Lehto, Ulriika; Lönnqvist, Jouko; Suvisaari, Jaana; Paunio, Tiina; Hennah, William

    2015-12-15

    Pre- and perinatal environmental factors have been shown to increase schizophrenia risk particularly when combined with genetic liability. The investigation of specific gene environment interactions in the etiology of psychiatric disorders has gained momentum. We used multivariate GEE regression modeling to investigate the interaction between genes of the DISC1 pathway and birth weight, in relation to schizophrenia susceptibility in a Finnish schizophrenia family cohort. The study sample consisted of 457 subjects with both genotype and birth weight information. Gender and place of birth were adjusted for in the models. We found a significant interaction between birth weight and two NDE1 markers in relation to increased schizophrenia risk: a four SNP haplotype spanning NDE1 (b=1.26, SE=0.5, p=0.012) and one of its constituent SNPs rs4781678 (b=1.33, SE=0.51, p=0.010). Specifically, high birth weight (>4000g) was associated with increased schizophrenia risk among subjects homozygous for the previously identified risk alleles. The study was based on a family study sample with high genetic loading for schizophrenia and thus our findings cannot directly be generalized as representing the general population. Our results suggest that the functions mediated by NDE1 during the early stages of neurodevelopment are susceptible to the additional disruptive effects of pre- and perinatal environmental factors associated with high birth weight, augmenting schizophrenia susceptibility. Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

  9. Rheological Link Between Polymer Melts with a High Molecular Weight Tail and Enhanced Formation of Shish-Kebabs

    Wingstrand, Sara Lindeblad; Shen, Bo; Kornfield, Julie A.

    2017-01-01

    Presence of an ultra high molecular weight (UHMw) fraction in flowingpolymer melts is known to facilitate formation of oriented crystalline structures significantly. The UHMw fraction manifests itself as a minor tail in the molar mass distribution and is hardly detectable in the canonical...... a clear increase in extensional stress that is directly correlated with the crystalline orientation of the quenched samples. Extensional rheology, particularly, in combination with linear creep measurements, thus, enables the conformational evolution of the UHMw-tail to be studied and linked...

  10. The low molecular weight protein PsaI stabilizes the light-harvesting complex II docking site of photosystem I

    Plöchinger, Magdalena; Torabi, Salar; Rantala, Marjaana

    2016-01-01

    PsaI represents one of three low molecular weight peptides of PSI. Targeted inactivation of the plastid PsaI gene in Nicotiana tabacum has no measurable effect on photosynthetic electron transport around PSI or on accumulation of proteins involved in photosynthesis. Instead, the lack of Psa......I destabilizes the association of PsaL and PsaH to PSI, both forming the light-harvesting complex (LHC)II docking site of PSI. These alterations at the LHCII binding site surprisingly did not prevent state transition but led to an increased incidence of PSI-LHCII complexes, coinciding with an elevated...

  11. Antifungal activity of low molecular weight chitosan produced from non-traditional marine resources

    Francisco Pires Avelelas

    2014-06-01

    Full Text Available The four plants pathogens, Botrytis cinerea, Phytophthora cinnamomi, Cryphonectria parasitica and Heterobasidion annosum are responsible for several diseases affecting different plant species in Portugal, such as pines (H. annosum, chestnuts (P. cinnamomi and C. parasitica and eucalyptus (B. cinerea. These pathogens incurs in large economic losses, and ultimately causes the death of these plants. The use of biopolymers as antimicrobial agents, such as chitosan (derived from chitin, is increasing, in order to reduce the negative impact of conventional chemical treatments on the environment, avoiding health risks. Therefore, eco-friendly polymers were produced through (1 N-acetylation with addition of acetic anhydride and (2 hydrogen peroxide of chitosan samples, obtained from two different sources: shrimp (commercial chitosan and swimming crab bycatch specie Polybius henslowii. The chemical structure and molecular weight of the prepared chitosan derivatives, water soluble chitosan (WSC and chitooligosaccharides (COS, was confirmed by Fourier Transform Infrared (FT-IR and Gel Permeation Chromatography (GPC and their antifungal activity evaluated against Botrytis cinerea, Phytophthora cinnamomi, Cryphonectria parasitica and Heterobasidion annosum. The concentration range varied from 0.0125 to 0.1 mg/mL and inhibition percentages were determined by differences in radial growth on the agar plates for all species. Although not all species tested exhibited equal vulnerability towards the concentrations range, antifungal activity of chitosan samples proved to be dependent, increasing the inhibitory capacity with lower concentrations. The results obtained support the use of chitosan fromPolybius henslowii when compared with commercial chitosan with shrimp towards antifungal approaches, suggesting that chitin producers can rely on this crab waste as a raw material for chitin extraction, adding value to this bycatch specie. Financial support was obtained

  12. Low birth weight may increase body fat mass in adult women with polycystic ovarian syndrome

    Sonia Minooee

    2016-05-01

    Full Text Available Background: Women engaged with polycystic ovarian syndrome (PCOS, as the commonest endocrine disorder, are known to have a specific type of adiposity. Birth weight is among different contributors reported to be responsible for this diversity. Objective: We aimed to compare the relation between birth weight and body fat mass (BFM/ body lean mass (BLM in PCOS and their age and body mass index (BMI matched normal controls. Materials and Methods: In this case-control study, a total number of 70 reproductive aged women, diagnosed with PCOS and 70 age- BMI matched healthy women without hirsutism and/or ovulatory dysfunction were recruited., control group had no polycystic ovaries in ultrasonographic scans. A detailed history of birth weight was taken and was divided into the following categories: <2,500 (low birth weight, LBW and 2,500-4,000 (normal birth weight; NBW. Results: Results showed that LBW prevalence was higher in women with PCOS than in controls (19.3% (27 vs. 15.7% (22. Also body fat and lean mass (BFM, BLM have increased in adult women with PCOS who were born underweight compared to their normal (19.8±9.05 vs. 12.9±4.5, p=0.001 and 48.9±6.9 vs. 43.2±5.8, p=0.004 respectively. Conclusion: Fetal birth weight influences on the adulthood obesity, BFM and BLM. This impact is different among women with and without PCOS

  13. Effect of Molecular Weight on the Properties of Liquid Epoxidized Natural Rubber Acrylate (LENRA)/ Silica Hybrid Composites

    Eda Yuhana Ariffin; Azizan Ahmad; Dahlan Mohd; Mahathir Mohamed

    2011-01-01

    This paper reports on the effect of molecular weight on the morphological and mechanical properties of liquid epoxidized natural rubber acrylate (LENRA)/ silica hybrid composites prepared by sol-gel technique. The sol-gel reaction was conducted at different concentration of tetraethyl orthosilicate (TEOS), used as a precursor of silica. TEOS were introduced in 10, 20, 30, 40 and 50 parts per hundred rubber (phr) in the composites. Two different molecular weights of ENR were used to study the effect of molecular weight on the mechanical and morphological properties of the compounds. These compounds were cured by ultraviolet (UV) irradiation. The mechanical properties were studied through pendulum hardness and scratch tests. Higher molecular weight of ENR showed better mechanical properties than lower molecular weight. Transmission electron microscope was used to determine the silica size and to study the distribution and dispersion of the silica particles. High molecular weight showed greater distribution and dispersion of silica particles with diameter of 13 - 256 nm. Morphological and mechanical properties of LENRA/ silica hybrid composites were improved by using high molecular weight of ENR. (author)

  14. The influence of polyanion molecular weight on polyelectrolyte multilayers at surfaces: elasticity and susceptibility to saloplasticity of strongly dissociated synthetic polymers at fluid-fluid interfaces.

    Cramer, Ashley D; Dong, Wen-Fei; Benbow, Natalie L; Webber, Jessie L; Krasowska, Marta; Beattie, David A; Ferri, James K

    2017-09-13

    We studied the interfacial mechanical properties of polyelectrolyte multilayer assemblies of poly(diallylamine hydrochloride) (PAH) and poly(4-styrenesulfonate)sodium salt (PSS) at the air-water interface using axisymmetric drop shape analysis (ADSA) during hydrostatic inflation as a function of aqueous salt concentration and two different polyanion molecular weights (M w ∼ 13 and 70 kDa). Surface elastic moduli (G s ) ranged from 50 to 300 mN m -1 . Using the measured film thickness, the bulk moduli (G) ranged from 10 to 90 MPa consistent with elastomeric solids. This solid-like interface was evidenced by a systematic departure of the inflated shape from the Young-Laplace equation, which assumes a liquid-like interface. Surface elastic moduli increased and bulk elastic moduli decreased with increasing nanomembrane transverse dimension, and multilayers with the lower molecular weight anion were more transversely compact than those of higher molecular weight and displayed a larger elastic modulus. The bulk moduli of both types of multilayer assemblies asymptotically approach a constant value for films with more than two bilayers of polyelectrolyte, consistent with the observed transition from a 'glassy' to 'rubbery' state. Both types of multilayer assemblies displayed plasticization with increasing sodium chloride concentration in the adjoining aqueous phase, i.e. saloplasticity, and exhibited a transition from elastic to plastic response to deformation. The restored mobility of the polyelectrolyte resulting from the shift from intrinsic to extrinsic charge complexation, restores fluidity to the interface and is evidenced by experimental observation of a liquid-like interface when loaded. The higher molecular weight polyanion multilayers plasticized at lower salt concentrations suggesting that the lower melting point of the higher molecular weight polyanion assembly is attributable to a lesser extent of electrostatic cross-linking underscoring the unconventional

  15. Euglycemia in Diabetic Rats Leads to Reduced Liver Weight via Increased Autophagy and Apoptosis through Increased AMPK and Caspase-3 and Decreased mTOR Activities

    Jun-Ho Lee

    2015-01-01

    Full Text Available Euglycemia is the ultimate goal in diabetes care to prevent complications. However, the benefits of euglycemia in type 2 diabetes are controversial because near-euglycemic subjects show higher mortality than moderately hyperglycemic subjects. We previously reported that euglycemic-diabetic rats on calorie-control lose a critical liver weight (LW compared with hyperglycemic rats. Here, we elucidated the molecular mechanisms underlying the loss of LW in euglycemic-diabetic rats and identified a potential risk in achieving euglycemia by calorie-control. Sprague-Dawley diabetic rats generated by subtotal-pancreatectomy were fed a calorie-controlled diet for 7 weeks to achieve euglycemia using 19 kcal% (19R or 6 kcal% (6R protein-containing chow or fed ad libitum (19AL. The diet in both R groups was isocaloric/kg body weight to the sham-operated group (19S. Compared with 19S and hyperglycemic 19AL, both euglycemic R groups showed lower LWs, increased autophagy, and increased AMPK and caspase-3 and decreased mTOR activities. Though degree of insulin deficiency was similar among the diabetic rats, Akt activity was lower, and PTEN activity was higher in both R groups than in 19AL whose signaling patterns were similar to 19S. In conclusion, euglycemia achieved by calorie-control is deleterious in insulin deficiency due to increased autophagy and apoptosis in the liver via AMPK and caspase-3 activation.

  16. In vitro fermentation and prebiotic potential of novel low molecular weight polysaccharides derived from agar and alginate seaweeds.

    Ramnani, Priya; Chitarrari, Roberto; Tuohy, Kieran; Grant, John; Hotchkiss, Sarah; Philp, Kevin; Campbell, Ross; Gill, Chris; Rowland, Ian

    2012-02-01

    Fermentation properties and prebiotic potential of novel low molecular weight polysaccharides (LMWPs) derived from agar and alginate bearing seaweeds was investigated. Ten LMWPs were supplemented to pH, temperature controlled anaerobic batch cultures inoculated with human feces from three donors, in triplicate. Microbiota changes were monitored using Fluorescent in-situ hybridization and short chain fatty acids, the fermentation end products were analysed using gas chromatography. Of the ten LMWPs tested, Gelidium seaweed CC2253 of molecular weight 64.64 KDa showed a significant increase in bifidobacterial populations from log(10) 8.06 at 0 h to log(10) 8.55 at 24 h (p = 0.018). For total bacterial populations, alginate powder CC2238 produced a significant increase from log(10) 9.01 at 0 h to log(10) 9.58 at 24 h (p = 0.032). No changes were observed in the other bacterial groups tested viz. Bacteroides, Lactobacilli/Enterococci, Eubacterium rectale/Clostridium coccoides and Clostridium histolyticum. The polysaccharides also showed significant increases in total SCFA production, particularly acetic and propionic acids, indicating that they were readily fermented. In conclusion, some LMWPs derived from agar and alginate bearing seaweeds were fermented by gut bacteria and exhibited potential to be used a novel source of prebiotics. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Association of increased monetary cost of dietary intake, diet quality and weight management in Spanish adults.

    Schröder, Helmut; Serra-Majem, Luis; Subirana, Isaac; Izquierdo-Pulido, Maria; Fitó, Montserrat; Elosua, Roberto

    2016-03-14

    Higher monetary diet cost is associated with healthier food choices and better weight management. How changes in diet cost affect changes in diet quality and weight remains unknown. The aim of this study was to assess the impact of changes in individual monetary diet cost on changes in diet quality, measured by the modified Mediterranean diet score recommendations (MDS-rec) and by energy density (ED), as well as changes in weight and BMI. We conducted a prospective, population-based study of 2181 male and female Spaniards aged between 25 and 74 years, who were followed up to the 2009-2010 academic year. We measured weight and height and recorded dietary data using a validated FFQ. Average food cost was calculated from official Spanish government data. We fitted multivariate linear and logistic regression models. The average daily diet cost increased from 3·68(SD0.0·89)€/8·36 MJ to 4·97(SD1·16)€/8·36 MJ during the study period. This increase was significantly associated with improvement in diet quality (Δ ED and Δ MDS-rec; Pcost per 8·36 MJ was associated with a decrease of 0·3 kg in body weight (P=0·02) and 0·1 kg/m(2) in BMI (P=0·04). These associations were attenuated after adjusting for changes in diet quality indicators. An improvement in diet quality and better weight management were both associated with an increase in diet cost; this could be considered in food policy decisions.

  18. Step Tracking with Goals Increases Children's Weight Loss in Behavioral Intervention.

    Staiano, Amanda E; Beyl, Robbie A; Hsia, Daniel S; Jarrell, Amber R; Katzmarzyk, Peter T; Mantzor, Savarra; Newton, Robert L; Tyson, Patrice

    2017-08-01

    This study examined the influence of step goals with pedometers to improve children's weight loss, physical activity, and psychosocial health during obesity treatment. Overweight and obese children ages 8-17 years (n = 105) participated in a 10-week family-based weight management intervention, including physical activity, nutrition, and behavioral modification. A quasi-experimental design was used to group eight cohorts into three conditions: no pedometer (n = 24), pedometer only (n = 25), and pedometer with step goals (i.e., 500 steps/day weekly increase above baseline; n = 56). Height and weight were measured at baseline and week 10 and used to calculate BMI. Analysis of covariance was performed to examine difference by condition for change in weight, BMI, and BMI z-score, controlling for age and baseline value. Differences in steps per day and psychosocial health were compared between the two pedometer conditions. Participants were 12.4 ± 2.5 years of age, including 70% girls and 64% African Americans. The pedometer with goals condition significantly reduced BMI (p = 0.02) and BMI z-score (p = 0.01) compared with the no-pedometer group. The pedometer with goals condition significantly increased steps per day (+1185 ± 425 steps/day) compared with the pedometer-only condition (-162 ± 620 steps/day; p goals was an effective approach to produce weight loss. Further work is needed to increase the strength of interventions to achieve clinically meaningful weight reduction for children with obesity.

  19. Ballistic behaviour of ultra-high molecular weight polyethylene: effect of gamma radiation

    Alves, Andreia L.S.; Nascimento, Lucio F.C.; Miguez Suarez, Joao Carlos

    2004-01-01

    The fiber reinforced polymer matrix composites (PMCs) are considered excellent engineering materials. In structural applications, when a high strength-to-weight ratio is fundamental for the design, PMCs are successfully replacing many conventional materials. Since World War II textile materials have been used as ballistic armor. Materials manufactured with ultrahigh molecular weight polyethylene (UHMWPE) fibers are used in the production of armor materials, for personnel protection and armored vehicles. As these have been developed and commercialized more recently, there is not enough information about the action of the ionizing radiation in the ballistic performance of this armor material. In the present work the ballistic behavior of composite plates manufactured with ultrahigh molecular weight polyethylene (UHMWPE) fibers were evaluated after exposure to gamma radiation. The ballistic tests results were related to the macromolecular modifications induced by the environmental degradation through mechanical (hardness, impact and flexure) and physicochemical (infrared spectroscopy, differential scanning calorimetry and thermal gravimetric analysis) tests. Our results indicate that gamma irradiation induces modifications in the UHMWPE macromolecular chains, altering the mechanical properties of the composite and decreasing, for higher radiation doses, its ballistic performance. These results are presented and discussed. (author)

  20. 99m-Tc-aprotinin; a low molecular weight protein for the study of renal function

    Bianchi, C.; Donadio, C.; Tramonti, G.; Lorusso, P.; Bellitto, L.; Lunghi, F.

    1982-01-01

    Aprotinin (A), a low molecular weight polypeptide (6500 daltons), is a protease inhibitor which is electively accumulated in the kidney of animals. If labelled with Tcsup(99m), A is an excellent agent for renal imaging. Pharmacokinetics of A-Tcsup(99m) was studied in 53 renal patients with different degrees of renal impairment. In patients with normal or slightly impaired renal function the plasma cl of A-Tcsup(99m) was lower than the GFR (mean ratio plasma cl A-Tcsup(99m)/GFR = 0.68+-0.22 SD). In patients with renal failure, the plasma cl exceeded the GFR (mean ratio 3.35). The apparent distribution volume of A-Tcsup(99m) (percent of body weight) was 15.4+-2.5 SD. A-Tcsup(99m) was markedly and rapidly accumulated in the kidneys. In patients with unilateral kidney disease the accumulation curve of the affected kidney was flatter than that of the contralateral kidney. In 4 of these patients the functional difference between the two kidneys as given by renal accumulation of A-Tcsup(99m) (2 hrs after injection) was lower than that of GFR. Urinary excretion of radioactivity in the first 2 hrs after i.v. injection of A-Tcsup(99m) was negligible (2.4+-1.6 SD percent of the dose). Conclusions: Labelled aprotinin is promising for the study of renal handling of low molecular weight proteins and for the measurement of unilateral renal function. (Author)

  1. Weighting sequence variants based on their annotation increases power of whole-genome association studies

    Sveinbjornsson, Gardar; Albrechtsen, Anders; Zink, Florian

    2016-01-01

    The consensus approach to genome-wide association studies (GWAS) has been to assign equal prior probability of association to all sequence variants tested. However, some sequence variants, such as loss-of-function and missense variants, are more likely than others to affect protein function...... for the family-wise error rate (FWER), using as weights the enrichment of sequence annotations among association signals. We show that this weighted adjustment increases the power to detect association over the standard Bonferroni correction. We use the enrichment of associations by sequence annotation we have...

  2. Mucin Agarose Gel Electrophoresis: Western Blotting for High-molecular-weight Glycoproteins.

    Ramsey, Kathryn A; Rushton, Zachary L; Ehre, Camille

    2016-06-14

    Mucins, the heavily-glycosylated proteins lining mucosal surfaces, have evolved as a key component of innate defense by protecting the epithelium against invading pathogens. The main role of these macromolecules is to facilitate particle trapping and clearance while promoting lubrication of the mucosa. During protein synthesis, mucins undergo intense O-glycosylation and multimerization, which dramatically increase the mass and size of these molecules. These post-translational modifications are critical for the viscoelastic properties of mucus. As a result of the complex biochemical and biophysical nature of these molecules, working with mucins provides many challenges that cannot be overcome by conventional protein analysis methods. For instance, their high-molecular-weight prevents electrophoretic migration via regular polyacrylamide gels and their sticky nature causes adhesion to experimental tubing. However, investigating the role of mucins in health (e.g., maintaining mucosal integrity) and disease (e.g., hyperconcentration, mucostasis, cancer) has recently gained interest and mucins are being investigated as a therapeutic target. A better understanding of the production and function of mucin macromolecules may lead to novel pharmaceutical approaches, e.g., inhibitors of mucin granule exocytosis and/or mucolytic agents. Therefore, consistent and reliable protocols to investigate mucin biology are critical for scientific advancement. Here, we describe conventional methods to separate mucin macromolecules by electrophoresis using an agarose gel, transfer protein into nitrocellulose membrane, and detect signal with mucin-specific antibodies as well as infrared fluorescent gel reader. These techniques are widely applicable to determine mucin quantitation, multimerization and to test the effects of pharmacological compounds on mucins.

  3. Efficacy and safety of once daily low molecular weight heparin (tinzaparin sodium) in high risk pregnancy.

    Ní Ainle, Fionnuala

    2008-10-01

    Low molecular weight heparin (LMWH) is widely regarded as the anticoagulant treatment of choice for the prevention and treatment of venous thromboembolism during pregnancy. However, previous studies have demonstrated that the pharmacokinetic profiles of LMWH vary significantly with increasing gestation. Consequently, it remains unclear whether LMWH regimens recommended for use in nonpregnant individuals can be safely extrapolated to pregnant women. The aims of this study were to assess the safety and the efficacy of tinzaparin sodium (Innohep) administered only once daily during pregnancy. A systematic retrospective review identified a cohort of 37 high-risk pregnancies which had been managed using tinzaparin 175 IU\\/kg once daily. In 26 cases, the index pregnancy had been complicated by development of an acute venous thromboembolism (17 deep vein thrombosis and nine pulmonary embolism). For each individual, case notes were examined and data extracted using a predetermined questionnaire. No episodes of recurrent venous thromboembolism were identified amongst this cohort of pregnancies managed using once daily LMWH administration. However, two unusual thrombotic complications were observed, including a parietal infarct in one patient, and a postpartum cerebral venous thrombosis in another. Once daily tinzaparin was well tolerated, with no cases of heparin-induced thrombocytopaenia, symptomatic osteoporosis, or foetal malformations. Tinzaparin dose modification based upon peak anti-Xa levels occurred in 45% of the cases examined. The present study is the largest study to have examined the clinical efficacy of once daily LMWH for use in pregnant women at high risk of venous thromboembolism. Our data support the safety and efficacy of antenatal tinzaparin at a dose of 175 IU\\/kg. In order to determine whether this once daily regimen provides equivalent (or indeed greater) thromboprophylaxis to twice daily LMWH regimens during pregnancy will require highly powered

  4. Increasing donor-recipient weight mismatch in pediatric orthotopic heart transplantation does not adversely affect outcome.

    Kanani, Mazyar; Hoskote, Aparna; Carter, Catherine; Burch, Michael; Tsang, Victor; Kostolny, Martin

    2012-02-01

    postoperative extracorporeal membrane oxygenator (ECMO) support (p recipient weight ratio of 3. These encouraging findings cautiously justify this policy, in an era when marginal donors are increasingly sought.

  5. Enhanced nutrition improves growth and increases blood adiponectin concentrations in very low birth weight infants

    Elin W. Blakstad

    2016-12-01

    Full Text Available Background: Adequate nutrient supply is essential for optimal postnatal growth in very low birth weight (VLBW, birth weight<1,500 g infants. Early growth may influence the risk of metabolic syndrome later in life. Objective: To evaluate growth and blood metabolic markers (adiponectin, leptin, and insulin-like growth factor-1 (IGF-1 in VLBW infants participating in a randomized nutritional intervention study. Design: Fifty VLBW infants were randomized to an enhanced nutrient supply or a standard nutrient supply. Thirty-seven infants were evaluated with growth measurements until 2 years corrected age (CA. Metabolic markers were measured at birth and 5 months CA. Results: Weight gain and head growth were different in the two groups from birth to 2 years CA (weight gain: pinteraction=0.006; head growth: pinteraction=0.002. The intervention group improved their growth z-scores after birth, whereas the control group had a pronounced decline, followed by an increase and caught up with the intervention group after discharge. At 5 months CA, adiponectin concentrations were higher in the intervention group and correlated with weight gain before term (r=0.35 and nutrient supply (0.35≤r≤0.45. Leptin concentrations correlated with weight gain after term and IGF-1 concentrations with length growth before and after term and head growth after term (0.36≤r≤0.53. Conclusion: Enhanced nutrient supply improved early postnatal growth and may have prevented rapid catch-up growth later in infancy. Adiponectin concentration at 5 months CA was higher in the intervention group and correlated positively with early weight gain and nutrient supply. Early nutrition and growth may affect metabolic markers in infancy.Clinical Trial Registration (ClinicalTrials.gov no.: NCT01103219

  6. Incidence of postpartum haemorrhage in women receiving therapeutic doses of low-molecular-weight heparin: results of a retrospective cohort study

    Roshani, Sara; Cohn, Danny M.; Stehouwer, Alexander C.; Wolf, Hans; van der Post, Joris A. M.; Büller, Harry R.; Kamphuisen, Pieter W.; Middeldorp, Saskia

    2011-01-01

    Background Low-molecular-weight heparin (LMWH) is the drug of choice to prevent venous thrombosis in pregnancy, but the optimal dose for prevention while avoiding bleeding is unclear. This study investigated whether therapeutic doses of LMWH increase the incidence of postpartum haemorrhage (PPH) in

  7. Incidence of postpartum haemorrhage in women receiving therapeutic doses of low-molecular-weight heparin : results of a retrospective cohort study

    Roshani, Sara; Cohn, Danny M; Stehouwer, Alexander C; Wolf, Hans; van der Post, Joris A M; Büller, Harry R; Kamphuisen, Pieter W; Middeldorp, Saskia

    2011-01-01

    Background Low-molecular-weight heparin (LMWH) is the drug of choice to prevent venous thrombosis in pregnancy, but the optimal dose for prevention while avoiding bleeding is unclear. This study investigated whether therapeutic doses of LMWH increase the incidence of postpartum haemorrhage (PPH) in

  8. Low-molecular-weight carbohydrate Pentaisomaltose may replace dimethyl sulfoxide as a safer cryoprotectant for cryopreservation of peripheral blood stem cells

    Svalgaard, Jesper Dyrendom; Haastrup, Eva Kannik; Reckzeh, Kristian

    2016-01-01

    -related side effects, there is an increasing demand for DMSO-free alternatives. We therefore investigated whether Pentaisomaltose (PIM), a low-molecular-weight carbohydrate (1 kDa), can be used for cryopreservation of peripheral blood stem cells, more specifically hematopoietic progenitor cell apheresis (HPC...

  9. Increased nocturnal fat oxidation in young healthy men with low birth weight

    Brøns, Charlotte; Lilleøre, S K; Jensen, C B

    2013-01-01

    OBJECTIVE: Low birth weight (LBW), a marker of disturbed fetal growth, is associated with adiposity and increased risk of type 2 diabetes (T2D). The aim of the study was to investigate whether LBW is associated with changes in 24-h energy expenditure (EE) and/or substrate utilization rates......, potentially contributing to the development of adiposity and/or T2D compared to matched control subjects. MATERIALS/METHODS: Forty-six young, healthy men were included in the study; 20 with LBW (= 10th percentile) and 26 control subjects with normal birth weight (NBW) (50th-90th percentile). The subjects were...... fed a weight maintenance diet and 24-h energy expenditure (EE), respiratory quotient (RQ), and substrate oxidation were assessed in a respiratory chamber. RESULTS: No differences in 24-h EE, RQ or substrate oxidation were observed between LBW and controls. Interestingly, the LBW group exhibited lower...

  10. Correlation between human maternal-fetal placental transfer and molecular weight of PCB and dioxin congeners/isomers.

    Mori, Chisato; Nakamura, Noriko; Todaka, Emiko; Fujisaki, Takeyoshi; Matsuno, Yoshiharu; Nakaoka, Hiroko; Hanazato, Masamichi

    2014-11-01

    Establishing methods for the assessment of fetal exposure to chemicals is important for the prevention or prediction of the child's future disease risk. In the present study, we aimed to determine the influence of molecular weight on the likelihood of chemical transfer from mother to fetus via the placenta. The correlation between molecular weight and placental transfer rates of congeners/isomers of polychlorinated biphenyls (PCBs) and dioxins was examined. Twenty-nine sample sets of maternal blood, umbilical cord, and umbilical cord blood were used to measure PCB concentration, and 41 sample sets were used to analyze dioxins. Placental transfer rates were calculated using the concentrations of PCBs, dioxins, and their congeners/isomers within these sample sets. Transfer rate correlated negatively with molecular weight for PCB congeners, normalized using wet and lipid weights. The transfer rates of PCB or dioxin congeners differed from those of total PCBs or dioxins. The transfer rate for dioxin congeners did not always correlate significantly with molecular weight, perhaps because of the small sample size or other factors. Further improvement of the analytical methods for dioxin congeners is required. The findings of the present study suggested that PCBs, dioxins, or their congeners with lower molecular weights are more likely to be transferred from mother to fetus via the placenta. Consideration of chemical molecular weight and transfer rate could therefore contribute to the assessment of fetal exposure. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Higher gestational weight gain is associated with increasing offspring birth weight independent of maternal glycemic control in women with type 1 diabetes

    Secher, Anna L; Parellada, Clara B; Ringholm, Lene

    2014-01-01

    ; P = 0.02) and birth weight SD score (β = 0.06; P = 0.008) when adjusted for prepregnancy BMI, HbA1c at 36 weeks, smoking, parity, and ethnicity. CONCLUSIONS: Higher gestational weight gain in women with type 1 diabetes was associated with increasing offspring birth weight independent of glycemic......OBJECTIVE: We evaluate the association between gestational weight gain and offspring birth weight in singleton term pregnancies of women with type 1 diabetes. RESEARCH DESIGN AND METHODS: One hundred fifteen consecutive women referred at ... (prepregnancy BMI Women...

  12. Measurement of low molecular weight silicon AMC to protect UV optics in photo-lithography environments

    Lobert, Jürgen M.; Miller, Charles M.; Grayfer, Anatoly; Tivin, Anne M.

    2009-03-01

    A new analytical method for semiconductor-specific applications is presented for the accurate measurement of low molecular weight, silicon-containing, organic compounds TMS, HMDSO and D3. Low molecular weight / low boiling point silicon-containing compounds are not captured for extended periods of time by traditional chemical filters but have the same potential to degrade exposure tool optical surfaces as their high molecular weight counterparts. Likewise, we show that capturing these compounds on sample traps that are commonly used for organic AMC analysis does not work for various reasons. Using the analytical method described here, TMS, HMDSO and D3 can be measured artifact-free, with at least a 50:1 peak-to-noise ratio at the method detection limit, determined through the Hubaux-Vos method and satisfying a conservative 99% statistical confidence. Method detection limits for the compounds are 1-6 ppt in air. We present calibration curve, capacity, capture efficiency, break-through and repeatability data to demonstrate robustness of method. Seventy-one real-world samples from 26 projects taken in several fab environments show that TMS is found in concentrations 100 times higher than those of HMDSO and D3. All compounds are found in all environments in concentrations ranging from zero to 12 ppm, but most concentrations were below 50 ppb. All compounds are noticeably higher in litho-bays than in sub-fabs and we found all three compounds inside of two exposure tools, suggesting cleanroom and/or tool-internal contamination sources.

  13. High molecular weight hyaluronan mediates the cancer resistance of the naked mole-rat

    Tian, Xiao; Azpurua, Jorge; Hine, Christopher; Vaidya, Amita; Myakishev-Rempel, Max; Ablaeva, Julia; Mao, Zhiyong; Nevo, Eviatar; Gorbunova, Vera; Seluanov, Andrei

    2013-01-01

    The naked mole-rat displays exceptional longevity, with a maximum lifespan exceeding 30 years1–3. This is the longest reported lifespan for a rodent species and is especially striking considering the small body mass of the naked mole-rat. In comparison, a similarly sized house mouse has a maximum lifespan of 4 years4,5. In addition to their longevity, naked mole-rats show an unusual resistance to cancer. Multi-year observations of large naked mole-rat colonies did not detect a single incidence of cancer2,6. Here we identify a mechanism responsible for the naked mole-rat’s cancer resistance. We found that naked mole-rat fibroblasts secrete extremely high molecular weight hyaluronan (HA), which is over five times larger than human or mouse HA. This high molecular weight HA accumulates abundantly in naked mole rat tissues due to the decreased activity of HA-degrading enzymes and a unique sequence of hyaluronan synthase 2 (HAS2). Furthermore, the naked mole-rat cells are more sensitive to HA signaling, as the naked mole rat cells have a higher affinity to HA than the mouse or human cells. Perturbation of the signaling pathways sufficient for malignant transformation of mouse fibroblasts fails to transform naked mole-rat cells. However, once high molecular weight HA is removed by either knocking down HAS2 or overexpressing the HA-degrading enzyme, Hyal2, naked mole-rat cells become susceptible to malignant transformation and readily form tumors in mice. We speculate that naked mole-rats have evolved a higher concentration of HA in the skin to provide skin elasticity needed for life in underground tunnels. This trait may have then been co-opted to provide cancer resistance and longevity to this species. PMID:23783513

  14. ADME-Tox profiling of some low molecular weight water soluble chitosan derivatives

    Adriana Isvoran

    2017-09-01

    Full Text Available Within this study we use a few computational tools for predicting absorption, distribution, metabolism, excretion and toxicity (ADME-Tox, pharmacokinetics profiles, toxic/adverse effects, carcinogenicity, cardiotoxicity and endocrine disruption of some of low molecular weight water soluble derivatives of chitosan that are used in wound healing. Investigated compounds do not possess drug-like properties, their pharmacokinetics profiles reveal poor gastrointestinal absorption and low skin penetration. Chitosan derivatives cannot pass the blood-brain barrier and they are not able to inhibit the enzymes of the cytochrome P450 that are involved in the metabolism of xenobiotics. They do not reflect carcinogenicity and cardiotoxicity and reveal only a low probability to be endocrine disruptors. The main side effects in humans of the investigated compounds are: weight loss, acidosis, gastrointestinal toxicity, respiratory failure. This information is especially important for professional exposure and accidental contamination with these compounds.

  15. A comparison study between different molecular weight polysaccharides derived from Lentinus edodes and their antioxidant activities in vivo.

    You, Ruxu; Wang, Kaiping; Liu, Jinyu; Liu, Maochang; Luo, Li; Zhang, Yu

    2011-12-01

    Polysaccharide purified Lentinus edodes (Berk.) Sing (Tricholomataceae) has been reported to attenuate oxidative stress in vitro. This study investigated whether polysaccharides from L. edodes with different molecular weight have protective effects against oxidative stress induced by D-galactose (D-gal) in vivo, and determined the specific relationship between molecular weight and antioxidant activity. In the present study, we successfully obtained three purified polysaccharides, coded as LT1, LT2, and LT3, and their molecular weights were 25.5, 306.2, and 605.4 kDa, respectively. The D-gal-treated mice received three polysaccharides once daily for 60 days. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), the content of malondialdehyde (MDA), and erythrocyte membrane fluidity were measured to evaluate the changes of the antioxidant ability. It was demonstrated that the administration of LT1, LT2, and LT3 could improve the antioxidant status to different levels. Furthermore, LT2 exhibited the highest antioxidant ability among these samples in vivo. Indeed, LT2 significantly decreased the content of MDA in liver (15.91 ± 0.31 versus 23.79 ± 1.18 nmol/mg protein for the model group, p < 0.05), enhanced the fluidity of erythrocyte membrane (2.458 ± 0.023 versus 2.167 ± 0.024 for the model group, p < 0.05), and increased the activities of SOD (147.19 ± 4.90 versus 82.26 ± 5.55 units/mg protein for the model group, p < 0.05) and GSH-Px (310.91 ± 6.24 versus 243.64 ± 6.77 units/mg protein for the model group, p < 0.05) in liver. The LT2 had a potential to be used as a novel natural antioxidant.

  16. Modification of polyelectrolyte microcapsules into a container for the low molecular weight compounds

    Goryacheva, O. A.; Gao, H.; Sukhorukov, G. B.

    2018-04-01

    Polyelectrolyte microcapsules are one of the most successful developments in the direction of target drug delivery. Nevertheless, to encapsulate low molecular weight compounds and to deliver the targeted drugs it is necessary to modify the surface of the microcapsules. Silica nanostructures obtained as result of hydrolysis of (3-Aminopropyl)- triethoxysilane (APTES) were used for the modification of the microcapsules. This material shows no toxic effect on cells and is capable of biodegradation. Amino-groups in the structure of APTES make it possible for further direct bioconjugation.

  17. Release of low molecular weight silicones and platinum from silicone breast implants.

    Lykissa, E D; Kala, S V; Hurley, J B; Lebovitz, R M

    1997-12-01

    We have conducted a series of studies addressing the chemical composition of silicone gels from breast implants as well as the diffusion of low molecular weight silicones (LM-silicones) and heavy metals from intact implants into various surrounding media, namely, lipid-rich medium (soy oil), aqueous tissue culture medium (modified Dulbecco's medium, DMEM), or an emulsion consisting of DMEM plus 10% soy oil. LM-silicones in both implants and surrounding media were detected and quantitated using gas chromatography (GC) coupled with atomic emission (GC-AED) as well as mass spectrometric (GC/MS) detectors, which can detect silicones in the nanogram range. Platinum, a catalyst used in the preparation of silicone gels, was detected and quantitated using inductive argon-coupled plasma/mass spectrometry (ICP-MS), which can detect platinum in the parts per trillion range. Our results indicate that GC-detectable low molecular weight silicones contribute approximately 1-2% to the total gel mass and consist predominantly of cyclic and linear poly-(dimethylsiloxanes) ranging from 3 to 20 siloxane [(CH3)2-Si-O] units (molecular weight 200-1500). Platinum can be detected in implant gels at levels of approximately 700 micrograms/kg by ICP-MS. The major component of implant gels appears to be high molecular weight silicone polymers (HM-silicones) too large to be detected by GC. However, these HM-silicones can be converted almost quantitatively (80% by mass) to LM-silicones by heating implant gels at 150-180 degrees C for several hours. We also studied the rates at which LM-silicones and platinum leak through the intact implant outer shell into the surrounding media under a variety of conditions. Leakage of silicones was greatest when the surrounding medium was lipid-rich, and up to 10 mg/day LM-silicones was observed to diffuse into a lipid-rich medium per 250 g of implant at 37 degrees C. This rate of leakage was maintained over a 7-day experimental period. Similarly, platinum was

  18. Vitamin K antagonists or low-molecular-weight heparin for the long term treatment of symptomatic venous thromboembolism

    van der Heijden, J. F.; Hutten, B. A.; Büller, H. R.; Prins, M. H.

    2002-01-01

    BACKGROUND: People with venous thromboembolism are generally treated for five days with intravenous unfractionated heparin or subcutaneous low-molecular-weight heparin followed by three months of vitamin K antagonists treatment. Treatment with vitamin K antagonists requires regular laboratory

  19. Flexible mechanoprosthesis made from woven ultra-high-molecular-weight polyethylene fibres : proof of concept in a chronic sheep model

    Basir, Amir; Grobben, Remco B.; Cramer, Maarten Jan; van Herwaarden, Joost A.; Vink, Aryan; Pasterkamp, Gerard; Kluin, Jolanda; Gründeman, Paul F.

    2017-01-01

    OBJECTIVES: Ultra-high-molecular-weight polyethylene (UHMWPE) fibres are flexible, have high tensile strength, and platelet and bacterial adhesion is low. Therefore, UHMWPE may overcome limitations of current mechanical valves and bioprostheses. In this study, the biocompatibility and functionality

  20. Low carbohydrate, high fat diet increases C-reactive protein during weight loss.

    Rankin, Janet W; Turpyn, Abigail D

    2007-04-01

    Chronic inflammation is associated with elevated risk of heart disease and may be linked to oxidative stress in obesity. Our objective was to evaluate the effect of weight loss diet composition (low carbohydrate, high fat, LC or high carbohydrate, low fat, HC) on inflammation and to determine whether this was related to oxidative stress. Twenty nine overweight women, BMI 32.1 +/- 5.4 kg/m(2), were randomly assigned to a self-selected LC or HC diet for 4 wks. Weekly group sessions and diet record collections helped enhance compliance. Body weight, markers of inflammation (serum interleukin-6, IL-6; C-reactive protein, CRP) oxidative stress (urinary 8-epi-prostaglandin F2alpha, 8-epi) and fasting blood glucose and free fatty acids were measured weekly. The diets were similar in caloric intake (1357 kcal/d LC vs. 1361 HC, p=0.94), but differed in macronutrients (58, 12, 30 and 24, 59, 18 for percent of energy as fat, carbohydrate, and protein for LC and HC, respectively). Although LC lost more weight (3.8 +/- 1.2 kg LC vs. 2.6 +/- 1.7 HC, p=0.04), CRP increased 25%; this factor was reduced 43% in HC (p=0.02). For both groups, glucose decreased with weight loss (85.4 vs. 82.1 mg/dl for baseline and wk 4, p<0.01), while IL-6 increased (1.39 to 1.62 pg/mL, p=0.04). Urinary 8-epi varied differently over time between groups (p<0.05) with no consistent pattern. Diet composition of the weight loss diet influenced a key marker of inflammation in that LC increased while HC reduced serum CRP but evidence did not support that this was related to oxidative stress.

  1. Can exercise increase fitness and reduce weight in patients with schizophrenia and depression?

    Jesper eKrogh

    2014-07-01

    Full Text Available BackgroundPsychiatric patients have a reduced life expectancy of 15 to 20 years compared to the general population. Most years of lost life are due to excess mortality from somatic diseases. Sedentary lifestyle and medication is partly responsible for the high frequency of metabolic syndrome in this patient group and low levels of physical activity is associated with increased risk of cardiovascular disease, diabetes and all-cause mortality. This study aimed to review trials allocating patients with either schizophrenia or depression to exercise interventions for effect on cardiovascular fitness, strength and weight.MethodsWe searched Pubmed, Embase, and Psycinfo including randomized clinical trial allocating patients with either schizophrenia or depression to isolated exercise interventions.ResultsWe identified five trials including patients with schizophrenia and found little evidence that exercise could increase cardiovascular fitness or decrease weight. Nine exercise trials for patients with depression were identified increasing cardiovascular fitness by 11-30% and strength by 33-37%. No evidence in favor of exercise for weight reduction was found.ConclusionBased on the current evidence isolated exercise interventions are unlikely to improve cardiovascular fitness or induce weight loss in patients with schizophrenia. In patients with depression exercise interventions are likely to induce clinically relevant short term effects, however, due to lack of reporting little is known about the effect on cardiovascular fitness beyond the intervention and weight reduction. Future exercise trials regarding patients with mental illness should preferably measure changes in cardiovascular strength, repetition maximum and anthropometric outcomes. Ideally participants should be assessed beyond the intervention

  2. Inulin in Medicinal Plants (IV) : Reversed-Phase High-Performance Liquid Chromatography of Inulin after Acetylation : Molecular-Weight Distribution of Inulin in Medicinal Plants

    三野, 芳紀; 筒井, 聡美; 太田, 長世; YOSHIKI, MINO; SATOMI, TSUTSUI; NAGAYO, OTA; 大阪薬科大学; 大阪薬科大学; 大阪薬科大学; Osaka College of Pharmacy; Osaka College of Pharmacy; Osaka College of Pharmacy

    1985-01-01

    Reversed-phase high-performance liquid chromatography coupled with pre-acetylation enabled acculate molecular-weight assay of inulin in medicinal plants to be conducted. The results clearly showed that the molecular-weight distribution of inulin varied depending on the stage of growth: Small molecular weight inulin polymers were detected in large quantity in the earlier growth stage whereas large molecular weight inulin polymers at the flowering and post flowering period.

  3. Increased leucocyte Na-K ATPase in obesity: reversal following weight loss

    Turaihi, K.; Baron, D.N.; Dandona, P.

    1987-01-01

    Ouabain-sensitive 86 Rb influx and [ 3 H] ouabain binding capacity were investigated in the leucocytes of 17 obese patients and 15 control subjects. Both were significantly increased in the obese when compared with controls. Following dietary restriction and a 4% to 5% weight reduction in the obese over 2 weeks, [ 3 H] ouabain binding and ouabain-sensitive 86 Rb influx (a model for K+ influx) decreased to levels similar to those in controls. This shows that the number of Na-K ATPase sites on leucocyte membranes of the obese are significantly increased and that this is associated with accelerated 86 Rb transport. Since both of these indices decreased following 4% to 5% reduction in body weight while the patients were still obese, increased Na-K ATPase is neither a marker of nor cardinal to the pathogenesis of obesity. We conclude that (1) increase in Na-K ATPase units and 86 Rb influx are not characteristic of obesity itself and (2) dietary restriction over the short-term with limited weight reduction restores Na-K ATPase units and 86 Rb influx to normal

  4. Increased leucocyte Na-K ATPase in obesity: reversal following weight loss

    Turaihi, K.; Baron, D.N.; Dandona, P.

    1987-09-01

    Ouabain-sensitive /sup 86/Rb influx and (/sup 3/H) ouabain binding capacity were investigated in the leucocytes of 17 obese patients and 15 control subjects. Both were significantly increased in the obese when compared with controls. Following dietary restriction and a 4% to 5% weight reduction in the obese over 2 weeks, (/sup 3/H) ouabain binding and ouabain-sensitive /sup 86/Rb influx (a model for K+ influx) decreased to levels similar to those in controls. This shows that the number of Na-K ATPase sites on leucocyte membranes of the obese are significantly increased and that this is associated with accelerated /sup 86/Rb transport. Since both of these indices decreased following 4% to 5% reduction in body weight while the patients were still obese, increased Na-K ATPase is neither a marker of nor cardinal to the pathogenesis of obesity. We conclude that (1) increase in Na-K ATPase units and /sup 86/Rb influx are not characteristic of obesity itself and (2) dietary restriction over the short-term with limited weight reduction restores Na-K ATPase units and /sup 86/Rb influx to normal.

  5. Effect of molecular weight on radiation chemical degradation yield of chain scission of γ-irradiated chitosan in solid state and in aqueous solution

    Tahtat, Djamel; Mahlous, Mohamed; Benamer, Samah; Nacer Khodja, Assia; Larbi Youcef, Souad

    2012-01-01

    Chitosan A 1 , A 2 and A 3 with molecular weight of 471, 207 and 100 kDa respectively, produced from squid pen chitin was degraded by gamma rays in the solid state and in aqueous solution with various doses in air at ambient temperature. Effect of molecular weight on radiation chemical degradation yield of chain scission and degradation rate constants of γ-irradiated chitosan in solid state and in aqueous solution was investigated. The radiation chemical degradation yield G (s) and degradation rate values were calculated. The molecular weight changes were monitored by capillary viscometry method and the chemical structure changes were followed by UV analysis. The results showed that, the degradation of chitosan was faster in solution, than in solid state. The values of G (s) in solid state and in aqueous solution were respectively 1.1×10 −8 mol/J and 0.074×10 −7 mol/J for A 1 , 4.42×10 −8 mol/J and 0.28×10 −7 mol/J for A 2 and 6.08×10 −8 mol/J and 0.38×10 −7 mol/J for A 3 . Degradation rate constants values ranged from 0.41×10 −5 to 2.1×10 −5 kGy −1 in solid state, whereas in solution they ranged from 13×10 −5 to 68×10 −5 kGy −1 . The chitosan A 3 was more sensitive to radiolysis than A 1 and A 2 . The chain scission yield, G (s) and degradation rate constants seems to be greatly influenced by the initial molecular weight of the chitosan. Structural changes in irradiated chitosan are revealed by the apparition of absorption peaks at 261 and 295 nm, which could be attributed to the formation of carbonyl groups. In both conditions the peak intensity was higher in chitosan A 3 than in A 1 and A 2 , the oxidative products decreased with increasing molecular weight of chitosan. - Highlights: ► We investigated the effects of MW on G (s) value of γ-irradiated chitosan in solid and aqueous state. ► Chitosan with low molecular weight was more sensitive to radiolysis than high molecular weight. ► G (s) value and degradation rate

  6. Anti-Toxoplasma activity of various molecular weights and concentrations of chitosan nanoparticles on tachyzoites of RH strain.

    Teimouri, Aref; Azami, Sanaz Jafarpour; Keshavarz, Hossein; Esmaeili, Fariba; Alimi, Rasoul; Mavi, Sara Ayazian; Shojaee, Saeedeh

    2018-01-01

    Natural polysaccharides such as chitosan (CS) are widely used as antimicrobial agents. In recent years, and considering that CS has a strong antimicrobial potential, interest has been focused on antimicrobial activity of chitosan nanoparticles (CS NPs). The main factors affecting the antibacterial activity of chitosan include molecular weight (MW) and concentration. In this regard, the aim of this study was to produce various MWs and concentrations of CS NPs, through the ionic gelation method, and investigate their potential anti-parasitic activity against tachyzoites of Toxoplasma gondii RH strain. The MWs and degree of deacetylation of the CS were characterized using viscometric and acid-base titration methods, respectively. The efficacy of various MWs and concentrations of NPs was assessed by performing in vitro experiments for tachyzoites of T. gondii RH strain, such as MTT assay, scanning electron microscopy, bioassay in mice and PCR. In vivo experiment was carried out in BALB/c mice which were inoculated with tachyzoites of T. gondii RH strain and treated with various MWs of CS NPs. The results of in vitro and in vivo experiments revealed that anti- Toxoplasma activity strengthened as the CS NPs concentration increased and the MW decreased. In vitro experiment showed 100% mortality of tachyzoites at 500 and 1,000 ppm concentrations of low molecular weight (LMW) CS NPs after 180 min and at 2,000 ppm after 120 min. Furthermore, a 100% mortality of tachyzoites was observed at 1,000 and 2,000 ppm concentrations of medium molecular weight (MMW) CS NPs and at 2,000 ppm concentration of high molecular weight (HMW) CS NPs after 180 min. Growth inhibition rates of tachyzoites in peritoneal exudates of mice receiving low, medium and high MWs of CS NPs were found to be 86%, 84% and 79% respectively, compared to those of mice in sulfadiazine treatment group (positive control). Various MWs of CS NPs exhibited great anti- Toxoplasma efficiency against tachyzoites of RH

  7. Molecular weight distribution of electron and γ-ray irradiated PEEK measured by very high temperature GPC

    Nakahara, H.

    1996-01-01

    Poly(ether ether ketone)(PEEK) films were irradiated with electron beam in air and in helium. Gel fractions of the PEEK samples were determined as the ratio of the weight of insoluble fraction/total weigh by extracting the samples with 1-chloronaphthalene (1-CN) at 260degC. While unirradiated PEEK samples were dissolved in 1-CN completely, PEEK samples highly (10 - 50 MGy) irradiated in air were almost insoluble in the solvent. The weight-average molecular weight M w of soluble fractions of the samples were measured by very high temperature gel permeation chromatography (VHTGPC): it was found that the M w decreases with increasing dose. On the other hand, PEEK samples irradiated in helium gave gel fractions at lower doses (0 - 5 MGy) than in air. The PEEK films were also irradiated with 60 Co γ-rays in the dose range, i.e. from 0 to 5 MGy. The γ-irradiated PEEK samples were completely dissolved in 1-CN at 260degC. Their M w measured by VHTGPC decreases with increasing dose. (author)

  8. The kinetic and thermodynamic sorption and stabilization of multiwalled carbon nanotubes in natural organic matter surrogate solutions: The effect of surrogate molecular weight

    Li, Tingting; Lin, Daohui; Li, Lu; Wang, Zhengyu; Wu, Fengchang

    2014-01-01

    Styrene sulfonate (SS) and polystyrene sulfonates (PSSs) were used as surrogates of natural organic matter to study the effect of molecular weight (from 206.2 to 70,000 Da) on their sorption by a multiwalled carbon nanotube (MWCNT) and an activated carbon (AC) and on their stabilization of MWCNT suspension. Results indicate that surface-diffusion through the liquid-sorbent boundary was the rate-controlling step of the kinetic sorption of both MWCNTs and AC, and surface-occupying and pore-filling mechanisms respectively dominated the thermodynamic sorption of MWCNTs and AC. Sorption rates and capacities of MWCNTs and AC in molecular concentration of SS and PSS decreased with increasing molecular weight. The PSSs but not SS facilitated the stabilization of MWCNT suspension because of the increased electrosteric repulsion. The PSSs with more monomers had greater capabilities to stabilize the MWCNT suspension, but the capabilities were comparable after being normalized by the total monomer number. -- Highlights: • Surface-diffusion controlled the kinetic sorption of NOM surrogates to MWCNTs and AC. • Surface-occupying mechanism dominates the thermodynamic sorption of MWCNTs. • The sorption in molecular concentration decreased with increasing M w of the PSSs. • PSS but not SS stabilized MWCNT suspension through electrosteric repulsion. • Stabilization capabilities normalized by monomer number of the PSSs were comparable. -- Molecular weight of NOM influences its sorption on and stabilizing MWCNTs

  9. Effects of molecular weight of natural organic matter on cadmium mobility in soil environments and its carbon isotope characteristics

    Mahara, Y.; Kubota, T.; Wakayama, R.; Nakano-Ohta, T.; Nakamura, T.

    2007-01-01

    We investigated the role of natural organic matter in cadmium mobility in soil environments. We collected the dissolved organic matter from two different types of natural waters: pond surface water, which is oxic, and deep anoxic groundwater. The collected organic matter was fractionated into four groups with molecular weights (unit: Da (Daltons)) of 3 , 1-10 x 10 3 , 10-100 x 10 3 , and > 100 x 10 3 . The organic matter source was land plants, based on the carbon isotope ratios (δ 13 C/ 12 C). The organic matter in surface water originated from presently growing land plants, based on 14 C dating, but the organic matter in deep groundwater originated from land plants that grew approximately 4000 years ago. However, some carbon was supplied by the high-molecular-weight fraction of humic substances in soil or sediments. Cadmium interacted in a system of siliceous sand, fractionated organic matter, and water. The lowest molecular weight fraction of organic matter ( 3 ) bound more cadmium than did the higher molecular weight fractions. Organic matter in deep groundwater was more strongly bound to cadmium than was organic matter in surface water. The binding behaviours of organic matter with cadmium depended on concentration, age, molecular weight, and degradation conditions of the organic matter in natural waters. Consequently, the dissolved, low-molecular-weight fraction in organic matter strongly influences cadmium migration and mobility in the environment

  10. Weight increase and overweight are associated with DNA oxidative damage in skeletal muscle.

    de la Maza, María-Pía; Olivares, Daniela; Hirsch, Sandra; Sierralta, Walter; Gattás, Vivien; Barrera, Gladys; Bunout, Daniel; Leiva, Laura; Fernández, Mireya

    2006-12-01

    Weight maintenance within normal standards is recommended for prevention of conditions associated with oxidative injury. To compare oxidative damage in a post mitotic tissue, between adults differing in long-term energy balance. During hernia surgery, a sample of skeletal muscle was obtained in 17 non-obese adults. Subjects were divided into two groups according to their self-reported weight change: weight maintainers (WM) reported 5kg increment. Muscle immunohistochemistry for 8-hydroxy-deoxyguanosine (8OHdG), 4-Hydroxy-2-nonenal (4HNE), and TNF-alpha, as markers of oxidative injury and inflammation, were performed. As known positive controls for oxidative injury, we included 10 elderly subjects (66-101yr). Anthropometric measures and blood samples for clinical laboratory and serum cytokines (TNF-alpha and IL-6) were obtained. 8OHdG was higher in WG compared with WM (149.1+/-16.2 versus 117.8+/-29.5, P=0.03), and was associated with anthropometric indicators of fat accumulation. 4HNE was similar in WG compared with WM (10.9+/-7.6 versus 9.8+/-6.3) but noticeably higher in elderly subjects (21.5+/-15.3, P=0.059). TNF-alpha protein in WG was higher compared with WM (114.0+/-41.7 versus 70.1+/-23.3, P=0.025), and was associated with weight increase. Moderate self-reported weight increase, and body fat accumulation, suggesting long-term positive energy balance is associated with muscle DNA oxidative injury and inflammation.

  11. Relationship between Oversulfation and Conformation of Low and High Molecular Weight Fucoidans and Evaluation of Their in Vitro Anticancer Activity

    Myoung Lae Cho

    2010-12-01

    Full Text Available Low and high molecular weight fucoidans (F5-30K and F>30K were chemically modified through the addition of sulfate groups, and the effect of oversulfation on the in vitro anticancer activity was investigated. After the addition of sulfate groups, a considerable increase of 35.5 to 56.8% was observed in the sulfate content of the F5-30K fraction, while the sulfate content of the F>30K fraction increased to a lesser extent (from 31.7 to 41.2%. Significant differences in anticancer activity were observed between the oversulfated F5–30K and F>30K fractions, with activities of 37.3–68.0% and 20.6–35.8%, respectively. This variation in the anticancer activity of oversulfated fucoidan derivatives was likely due to differences in their sulfate content. The results suggest that the molecular conformation of these molecules is closely related to the extent of sulfation in the fucan backbones and that the sulfates are preferably substituted when the fucoidan polymers are in a loose molecular conformation.

  12. Passivation Using Molecular Halides Increases Quantum Dot Solar Cell Performance

    Lan, Xinzheng; Voznyy, Oleksandr; Kiani, Amirreza; Garcí a de Arquer, F. Pelayo; Abbas, Abdullah Saud; Kim, Gi-Hwan; Liu, Mengxia; Yang, Zhenyu; Walters, Grant; Xu, Jixian; Yuan, Mingjian; Ning, Zhijun; Fan, Fengjia; Kanjanaboos, Pongsakorn; Kramer, Illan; Zhitomirsky, David; Lee, Philip; Perelgut, Alexander; Hoogland, Sjoerd; Sargent, Edward H.

    2015-01-01

    © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Here we report a solution-based passivation scheme is developed featuring the use of molecular iodine and PbS colloidal quantum dots (CQDs). The improved passivation translates into a longer carrier diffusion length in the solid film. This allows thicker solar-cell devices to be built while preserving efficient charge collection, leading to a certified power conversion efficiency of 9.9%, which is a new record in CQD solar cells.

  13. Passivation Using Molecular Halides Increases Quantum Dot Solar Cell Performance.

    Lan, Xinzheng; Voznyy, Oleksandr; Kiani, Amirreza; García de Arquer, F Pelayo; Abbas, Abdullah Saud; Kim, Gi-Hwan; Liu, Mengxia; Yang, Zhenyu; Walters, Grant; Xu, Jixian; Yuan, Mingjian; Ning, Zhijun; Fan, Fengjia; Kanjanaboos, Pongsakorn; Kramer, Illan; Zhitomirsky, David; Lee, Philip; Perelgut, Alexander; Hoogland, Sjoerd; Sargent, Edward H

    2016-01-13

    A solution-based passivation scheme is developed featuring the use of molecular iodine and PbS colloidal quantum dots (CQDs). The improved passivation translates into a longer carrier diffusion length in the solid film. This allows thicker solar-cell devices to be built while preserving efficient charge collection, leading to a certified power conversion efficiency of 9.9%, which is a new record in CQD solar cells. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Passivation Using Molecular Halides Increases Quantum Dot Solar Cell Performance

    Lan, Xinzheng

    2015-11-18

    © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Here we report a solution-based passivation scheme is developed featuring the use of molecular iodine and PbS colloidal quantum dots (CQDs). The improved passivation translates into a longer carrier diffusion length in the solid film. This allows thicker solar-cell devices to be built while preserving efficient charge collection, leading to a certified power conversion efficiency of 9.9%, which is a new record in CQD solar cells.

  15. Modification of UV absorption profile of polymer film reflectors to increase solar-weighted reflectance

    Jorgensen, Gary; Gee, Randall C.; White, David

    2017-05-02

    Provided are reflective thin film constructions including a reduced number of layers, which provides for increased solar-weighted hemispherical reflectance and durability. Reflective films include those comprising an ultraviolet absorbing abrasion resistant coating over a metal layer. Also provided are ultraviolet absorbing abrasion resistant coatings and methods for optimizing the ultraviolet absorption of an abrasion resistant coating. Reflective films disclosed herein are useful for solar reflecting, solar collecting, and solar concentrating applications, such as for the generation of electrical power.

  16. THE SURFACE-MEDIATED UNFOLDING KINETICS OF GLOBULAR PROTEINS IS DEPENDENT ON MOLECULAR WEIGHT AND TEMPERATURE

    Patananan, A.N.; Goheen, S.C.

    2008-01-01

    The adsorption and unfolding pathways of proteins on rigid surfaces are essential in numerous complex processes associated with biomedical engineering, nanotechnology, and chromatography. It is now well accepted that the kinetics of unfolding are characterized by chemical and physical interactions dependent on protein deformability and structure, as well as environmental pH, temperature, and surface chemistry. Although this fundamental process has broad implications in medicine and industry, little is known about the mechanism because of the atomic lengths and rapid time scales involved. Therefore, the unfolding kinetics of myoglobin, β-glucosidase, and ovalbumin were investigated by adsorbing the globular proteins to non-porous cationic polymer beads. The protein fractions were adsorbed at different residence times (0, 9, 10, 20, and 30 min) at near-physiological conditions using a gradient elution system similar to that in high-performance liquid chromatography. The elution profi les and retention times were obtained by ultraviolet/visible spectrophotometry. A decrease in recovery was observed with time for almost all proteins and was attributed to irreversible protein unfolding on the non-porous surfaces. These data, and those of previous studies, fi t a positively increasing linear trend between percent unfolding after a fi xed (9 min) residence time (71.8%, 31.1%, and 32.1% of myoglobin, β-glucosidase, and ovalbumin, respectively) and molecular weight. Of all the proteins examined so far, only myoglobin deviated from this trend with higher than predicted unfolding rates. Myoglobin also exhibited an increase in retention time over a wide temperature range (0°C and 55°C, 4.39 min and 5.74 min, respectively) whereas ovalbumin and β-glucosidase did not. Further studies using a larger set of proteins are required to better understand the physiological and physiochemical implications of protein unfolding kinetics. This study confi rms that surface

  17. Purification of a large molecular weight transglutaminase substrate from liver plasma membranes

    Slife, C.W.; Morris, G.S.; Tyrrell, D.J.

    1986-01-01

    Transglutaminases are enzymes which catalyze the covalent crosslinking of proteins by forming epsilon(γ-glutamyl)lysine isopeptide linkages. In earlier studies, the authors reported that a large molecular weight protein aggregate in rat liver plasma membranes served as a substrate for a plasma membrane-associated transglutaminase. The enzyme specifically incorporated a lysine analog, [ 3 H]putrescine, into a protein complex which remained at the top of an acrylamide gel upon electrophoresis in SDS and reducing agents. The complex has now been isolated by extracting the plasma membranes with detergent (octylglucoside) resuspending the detergent insoluble residues in 6 M guanidine HCl and chromatographing the residue on a 4% agarose column in 6 M guanidine HCl. Most of the radioactivity is found in the void volume fractions from the column. SDS polyacrylamide gel electrophoresis shows that these fractions contain mostly proteins that do not enter the acrylamide gel. Since this purification procedure is essentially the same as that used to isolate a rat hepatocyte adhesion factor from rat liver plasma membranes it is possible that the large molecular weight transglutaminase substrate and the adhesion factor are contained in the same protein aggregate

  18. Single intra-articular injection of high molecular weight hyaluronic acid for hip osteoarthritis.

    Rivera, Fabrizio

    2016-03-01

    Intra-articular (IA) injection of hyaluronic acid (HA) into the hip joint appears to be safe and well tolerated but only a small number of randomized clinical trials in humans has been published. The objective of this prospective study was to evaluate the efficacy and safety of a single IA injection of high-molecular-weight (2800 kDa) HA (Coxarthrum) for hip osteoarthritis. All patients received a single IA administration of 2.5 % sodium hyaluronate (75 mg/3 mL) of high molecular weight. Fluoroscopy requires an iodized contrast medium (iopamidol, 1 ml) which highlights the capsule before administering HA. Patients were evaluated before IA injection (T0), after 3 months, after 6 months and after 1 year from injection. Results were evaluated by the Brief Pain Inventory (BPI II), Harris Hip Score and a visual analog scale of pain (pain VAS). All treated patients were considered for statistical analysis. Two hundred seven patients were included at T0. The mean age was 67 years (range 46-81). Regarding BPI severity score, changes in pain between T0 and the three following visits were statistically highly significant (p injection of Coxarthrum is effective from the third month and that the results are stable or continue to improve up to 1 year. IV.

  19. Comprehensive Analysis of Low-Molecular-Weight Human Plasma Proteome Using Top-Down Mass Spectrometry.

    Cheon, Dong Huey; Nam, Eun Ji; Park, Kyu Hyung; Woo, Se Joon; Lee, Hye Jin; Kim, Hee Cheol; Yang, Eun Gyeong; Lee, Cheolju; Lee, Ji Eun

    2016-01-04

    While human plasma serves as a great source for disease diagnosis, low-molecular-weight (LMW) proteome (mass spectrometry to analyze the LMW proteoforms present in four types of human plasma samples pooled from three healthy controls (HCs) without immunoaffinity depletion and with depletion of the top two, six, and seven high-abundance proteins. The LMW proteoforms were first fractionated based on molecular weight using gel-eluted liquid fraction entrapment electrophoresis (GELFrEE). Then, the GELFrEE fractions containing up to 30 kDa were subjected to nanocapillary-LC-MS/MS, and the high-resolution MS and MS/MS data were processed using ProSightPC 3.0. As a result, a total of 442 LMW proteins and cleaved products, including those with post-translational modifications and single amino acid variations, were identified. From additional comparative analysis of plasma samples without immunoaffinity depletion between HCs and colorectal cancer (CRC) patients via top-down approach, tens of LMW proteoforms, including platelet factor 4, were found to show >1.5-fold changes between the plasma samples of HCs and CRC patients, and six of the LMW proteins were verified by Western blot analysis.

  20. Analysis of sulfates on low molecular weight heparin using mass spectrometry: structural characterization of enoxaparin.

    Gupta, Rohitesh; Ponnusamy, Moorthy P

    2018-05-21

    Structural characterization of Low Molecular Weight Heparin (LMWH) is critical to meet biosimilarity standards. In this context, the review focuses on structural analysis of labile sulfates attached to the side-groups of LMWH using mass spectrometry. A comprehensive review of this topic will help readers to identify key strategies for tackling the problem related to sulfate loss. At the same time, various mass spectrometry techniques are presented to facilitate compositional analysis of LMWH, mainly Enoxaparin. Areas covered: This review summarizes findings on mass spectrometry application for LMWH, including modulation of sulfates, using enzymology and sample preparation approaches. Furthermore, popular open-source software packages for automated spectral data interpretation are also discussed. Successful use of LC/MS can decipher structural composition for LMWH and help evaluate their sameness or biosimilarity with the innovator molecule. Overall, the literature has been searched using PubMed by typing various search queries such as "enoxaparin", "mass spectrometry", "low molecular weight heparin", "structural characterization", etc. Expert commentary: This section highlights clinically relevant areas that need improvement to achieve satisfactory commercialization of LMWHs. It also primarily emphasizes the advancements in instrumentation related to mass spectrometry, and discusses building automated software for data interpretation and analysis.

  1. High Performance Shape Memory Polyurethane Synthesized with High Molecular Weight Polyol as the Soft Segment

    Manzoor Ahmad

    2012-05-01

    Full Text Available Shape memory polyurethanes (SMPUs are typically synthesized using polyols of low molecular weight (MW~2,000 g/mol as it is believed that the high density of cross-links in these low molecular weight polyols are essential for high mechanical strength and good shape memory effect. In this study, polyethylene glycol (PEG-6000 with MW ~6000 g/mol as the soft segment and diisocyanate as the hard segment were used to synthesize SMPUs, and the results were compared with the SMPUs with polycaprolactone PCL-2000. The study revealed that although the PEG-6000-based SMPUs have lower maximum elongations at break (425% and recovery stresses than those of PCL-based SMPUs, they have much better recovery ratios (up to 98% and shape fixity (up to 95%, hence better shape memory effect. Furthermore, PEG-based SMPUs showed a much shorter actuation time of < 10 s for up to 90% shape recovery compared to typical actuation times of tens of seconds to a few minutes for common SMPUs, demonstrated their great potential for applications in microsystems and other engineering components.

  2. Trypanosoma equiperdum Low Molecular Weight Proteins As Candidates for Specific Serological Diagnosis of Dourine

    Mirella Luciani

    2018-03-01

    Full Text Available The diagnosis of dourine can be difficult because the clinical signs of this disease in horses are similar to those of surra, caused by Trypanosoma evansi. Moreover, T. equiperdum and T. evansi are closely related and, so far, they cannot be distinguished using serological tests. In a previous work, the T. equiperdum protein pattern recognized by antibodies from dourine-infected horses and the humoral immune response kinetics were investigated by immunoblotting assay; a total of 20 sera from naturally and experimentally infected horses and from healthy animals were tested. Immunoblotting analysis showed that antibodies from infected horses specifically bind T. equiperdum low molecular weight proteins (from 16 to 35 kDa, which are not recognized by antibodies from uninfected horses. In this work, we tested other 615 sera (7 from naturally infected horses and 608 sera from healthy horses and donkeys: results confirmed the data obtained previously. In addition, six SDS-PAGE bands with molecular weight ranging from 10 to 37 kDa were analyzed by mass spectrometry, in order to identify immunogenic proteins that could be used as biomarkers for the diagnosis of dourine. A total of 167 proteins were identified. Among them, 37 were found unique for T. equiperdum. Twenty-four of them could represent possible candidate diagnostic antigens for the development of serological tests specific for T. equiperdum.

  3. A sulfuric-lactic acid process for efficient purification of fungal chitosan with intact molecular weight.

    Naghdi, Mitra; Zamani, Akram; Karimi, Keikhosro

    2014-02-01

    The most recent method of fungal chitosan purification, i.e., two steps of dilute sulfuric acid treatment, pretreatment of cell wall at room temperature for phosphate removal and extraction of chitosan from the phosphate free cell wall at high temperature, significantly reduces the chitosan molecular weight. This study was aimed at improvement of this method. In the pretreatment step, to choose the best conditions, cell wall of Rhizopus oryzae, containing 9% phosphate, 10% glucosamine, and 21% N-acetyl glucosamine, was treated with sulfuric, lactic, acetic, nitric, or hydrochloric acid, at room temperature. Sulfuric acid showed the best performance in phosphate removal (90%) and cell wall recovery (89%). To avoid depolymerisation of chitosan, hot sulfuric acid extraction was replaced with lactic acid treatment at room temperature, and a pure fungal chitosan was obtained (0.12 g/g cell wall). Similar pretreatment and extraction processes were conducted on pure shrimp chitosan and resulted in a chitosan recovery of higher than 87% while the reduction of chitosan viscosity was less than 15%. Therefore, the sulfuric-lactic acid method purified the fungal chitosan without significant molecular weight manipulation. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Molecular Weight and Structural Properties of Biodegradable PLA Synthesized with Different Catalysts by Direct Melt Polycondensation

    Hyung Woo Lee

    2015-09-01

    Full Text Available Production of biodegradable polylactic acid (PLA from biomassbased lactic acid is widely studied for substituting petro-based plastics or polymers. This study investigated PLA production from commercial lactic acid in a batch reactor by applying a direct melt polycondensation method with two kinds of catalyst, γ-aluminium(III oxide (γ-Al2O3 or zinc oxide (ZnO, in reduced pressure. The molecular weight of the synthesized PLA was determined by capillary viscometry and its structural properties were analyzed by functional group analysis using FT-IR. The yields of polymer production with respect to the theoretical conversion were 47% for γ-Al2O3 and 35% for ZnO. However, the PLA from ZnO had a higher molecular weight (150,600 g/mol than that from γ-Al2O3 (81,400 g/mol. The IR spectra of the synthesized PLA from both catalysts using polycondensation show the same behavior of absorption peaks at wave numbers from 4,500 cm-1 to 500 cm-1, whereas the PLA produced by two other polymerization methods – polycondensation and ring opening polymerization –showed a significant difference in % transmittance intensity pattern as well as peak area absorption at a wave number of 3,500 cm-1 as –OH vibration peak and at 1,750 cm-1 as –C=O carbonyl vibrational peak.

  5. Synthesis and characterization of high molecular weight hydrophobically modified polyacrylamide nanolatexes using novel nonionic polymerizable surfactants

    A.M. Al-Sabagh

    2013-12-01

    Full Text Available In this article, nine hydrophobically modified polyacrylamides (HM-PAM nanolatexes, were synthesized by copolymerizing the acrylamide monomer and novel polymerizable surfactants (surfmers. The reaction was carried out by inverse microemulsion copolymerization technique. The copolymerization was initiated by redox initiators composed of potassium peroxodisulphate and sodium bisulfite. The emulsion was stabilized using mixed tween 85 and span 80 as nonionic emulsifiers. The prepared HM-PAMs were classified into three groups according to the surfmers used in the copolymerization. The chemical structures of the prepared HM-PAMs were confirmed by FT-IR, 1H NMR and 13C NMR. The thermal properties were estimated with the thermal gravimetric analysis (TGA. The size and morphology of the prepared latexes were investigated by the dynamic light scattering (DLS and the High Resolution Transmission Electron Microscope (HRTEM. Finally, the molecular weights of the prepared copolymers were determined by the GPC and the viscosity average molecular weight method. They were situated between 1.58 × 106 and 0.89 × 106.

  6. Size-exclusion chromatography (HPLC-SEC) technique optimization by simplex method to estimate molecular weight distribution of agave fructans.

    Moreno-Vilet, Lorena; Bostyn, Stéphane; Flores-Montaño, Jose-Luis; Camacho-Ruiz, Rosa-María

    2017-12-15

    Agave fructans are increasingly important in food industry and nutrition sciences as a potential ingredient of functional food, thus practical analysis tools to characterize them are needed. In view of the importance of the molecular weight on the functional properties of agave fructans, this study has the purpose to optimize a method to determine their molecular weight distribution by HPLC-SEC for industrial application. The optimization was carried out using a simplex method. The optimum conditions obtained were at column temperature of 61.7°C using tri-distilled water without salt, adjusted pH of 5.4 and a flow rate of 0.36mL/min. The exclusion range is from 1 to 49 of polymerization degree (180-7966Da). This proposed method represents an accurate and fast alternative to standard methods involving multiple-detection or hydrolysis of fructans. The industrial applications of this technique might be for quality control, study of fractionation processes and determination of purity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. The effect of gamma irradiation and shelf aging in air on the oxidation of ultra-high molecular weight polyethylene

    Al-Ma'adeed, M.A.; Al-Qaradawi, I.Y.; Madi, N.; Al-Thani, N.J.

    2006-01-01

    This study has investigated the effect of shelf aging, for up to one year in air, on the properties of gamma-irradiated ultra-high molecular weight polyethylene (UHMWPE). A variety of techniques were used to characterize the properties of treated samples. Differential scanning calorimetery (DSC) was used to characterize the morphology. The extent of cross-linking in a polymer network was detected by swelling measurements. The durometer hardness test was used to measure the relative hardness of this material, and changes in density were also measured. Results from all these measurements were combined to explain the changes in the microstructure of the aged, irradiated UHMWPE. This study shows that crystallinity is increased with radiation dose and with aging due to chain scission, which leads to a reduction in the molecular weight of the material. This allows the chains to rearrange to form crystalline regions. Positron annihilation lifetime spectroscopy confirms these conclusions. Fractional free volumes have been deduced from lifetime parameters, which correlate with the data obtained by the other techniques

  8. Hemorrhagic shock and surgical stress alter distribution of labile zinc within high- and low-molecular-weight plasma fractions.

    Kelly, Edward; Mathew, Jeff; Kohler, Jonathan E; Blass, Amy L; Soybel, And David I

    2012-08-01

    Zinc ions (Zn) are essential for tissue repair following injury or stress. We hypothesize that during such stresses Zn is redistributed to labile pools in plasma components. Here we tested this hypothesis using a novel assay to monitor labile Zn in plasma in hemorrhagic shock. Adult rats in the shock group (S group) underwent hemorrhage and resuscitation. Blood samples were drawn at baseline and at 1, 4, and 24 h. The surgical control group (SC group) was anesthetized and instrumented, but not bled. Albumin, total Zn, and labile Zn levels were assayed in plasma. Binding capacity for Zn was assessed in high- and low-molecular-weight pools. Significant decreases in total Zn were observed by 24 h, in both S and SC groups. Albumin levels were significantly reduced in the S group at 1 and 4 h but restored at 24 h; significant changes were not observed in other groups. In whole plasma, labile Zn levels were stable initially in the S and SC groups, but declined at 24 h. In the high-molecular-weight pool, marked and significant impairment of binding was noted throughout all time periods following the shock period in the S group. Such changes were observed in the SC group of less intensity and duration. These experiments suggest that shock alters affinity of plasma proteins for Zn, promoting delivery to peripheral tissues during periods of increased Zn utilization.

  9. Hyperandrogenism Accompanies Increased Intra-Abdominal Fat Storage in Normal Weight Polycystic Ovary Syndrome Women

    Akopians, Alin L.; Madrigal, Vanessa K.; Ramirez, Emmanuel; Margolis, Daniel J.; Sarma, Manoj K.; Thomas, Albert M.; Grogan, Tristan R.; Haykal, Rasha; Schooler, Tery A.; Okeya, Bette L.; Abbott, David H.; Chazenbalk, Gregorio D.

    2016-01-01

    Context: Normal weight polycystic ovary syndrome (PCOS) women may have altered adipose structure-function underlying metabolic dysfunction. Objective: This study examines whether adipose structure-functional changes exist in normal weight PCOS women and correlate with hyperandrogenism and/or hyperinsulinemia. Design: This is a prospective cohort study. Setting: The setting was an academic medical center. Patients: Six normal weight PCOS women and 14 age- and body mass index-matched normoandrogenic ovulatory (NL) women were included. Intervention(s): All women underwent circulating hormone and metabolic measurements; frequently sampled intravenous glucose tolerance testing; total body dual-energy x-ray absorptiometry; abdominal magnetic resonance imaging; and SC abdominal fat biopsy. Main Outcome Measure(s): Circulating hormones and metabolites, body fat and its distribution, and adipocyte size were compared between PCOS and NL women, and were correlated with each other in all women. Results: Circulating LH and androgen levels were significantly greater in PCOS than NL women, as were fasting insulin levels, pancreatic β-cell responsiveness to glucose, and total abdominal fat mass. Intra-abdominal fat mass also was significantly increased in PCOS women and was positively correlated with circulating androgen, fasting insulin, triglyceride, and non-high-density lipoprotein cholesterol levels in all women. SC abdominal fat mass was not significantly increased in PCOS women, but contained a greater proportion of small SC abdominal adipocytes that positively correlated with serum androgen levels in all women. Conclusion: Hyperandrogenism in normal weight PCOS women is associated with preferential intra-abdominal fat deposition and an increased population of small SC abdominal adipocytes that could constrain SC adipose storage and promote metabolic dysfunction. PMID:27571186

  10. Hyperandrogenism Accompanies Increased Intra-Abdominal Fat Storage in Normal Weight Polycystic Ovary Syndrome Women.

    Dumesic, Daniel A; Akopians, Alin L; Madrigal, Vanessa K; Ramirez, Emmanuel; Margolis, Daniel J; Sarma, Manoj K; Thomas, Albert M; Grogan, Tristan R; Haykal, Rasha; Schooler, Tery A; Okeya, Bette L; Abbott, David H; Chazenbalk, Gregorio D

    2016-11-01

    Normal weight polycystic ovary syndrome (PCOS) women may have altered adipose structure-function underlying metabolic dysfunction. This study examines whether adipose structure-functional changes exist in normal weight PCOS women and correlate with hyperandrogenism and/or hyperinsulinemia. This is a prospective cohort study. The setting was an academic medical center. Six normal weight PCOS women and 14 age- and body mass index-matched normoandrogenic ovulatory (NL) women were included. All women underwent circulating hormone and metabolic measurements; frequently sampled intravenous glucose tolerance testing; total body dual-energy x-ray absorptiometry; abdominal magnetic resonance imaging; and SC abdominal fat biopsy. Circulating hormones and metabolites, body fat and its distribution, and adipocyte size were compared between PCOS and NL women, and were correlated with each other in all women. Circulating LH and androgen levels were significantly greater in PCOS than NL women, as were fasting insulin levels, pancreatic β-cell responsiveness to glucose, and total abdominal fat mass. Intra-abdominal fat mass also was significantly increased in PCOS women and was positively correlated with circulating androgen, fasting insulin, triglyceride, and non-high-density lipoprotein cholesterol levels in all women. SC abdominal fat mass was not significantly increased in PCOS women, but contained a greater proportion of small SC abdominal adipocytes that positively correlated with serum androgen levels in all women. Hyperandrogenism in normal weight PCOS women is associated with preferential intra-abdominal fat deposition and an increased population of small SC abdominal adipocytes that could constrain SC adipose storage and promote metabolic dysfunction.

  11. Enhanced hyluronic acid production in Streptococcus zooepidemicus by over expressing HasA and molecular weight control with Niscin and glucose

    Alireza Zakeri

    2017-12-01

    Full Text Available Hyaluronic acid (HA is a high molecular weight linear polysaccharide, endowed with unique physiological and biological properties. Given its unique properties, HA have unprecedented applications in the fields of medicine and cosmetics. The ever growing demand for HA production is the driving force behind the need for finding and developing novel and amenable sources of the HA producers. Microbial fermentation of Streptococcus zooepidemicus deemed as one the most expeditious and pervasive methods of HA production. Herein, a wild type Streptococcus zooepidemicus, intrinsically expressing high levels of HA, was selected and optimized for HA production. HasA gene was amplified and introduced into the wild type Streptococcus zooepidemicus, under the control of Nisin promoter. The HasA over-expression increased the HA production, while the molecular weight was decreased. In order to compensate for molecular weight loss, the glucose concentration was increased to an optimum amount of 90 g/L. It is hypostatizes that excess glucose would rectify the distribution of the monomers and each HasA molecule would be provided with sufficient amount of substrates to lengthen the HA molecules. Arriving at an improved strain and optimized cultivating condition would pave the way for industrial grade HA production with high quality and quantity. Keywords: Streptococcus zooepidemicus, Hyaluronic acid, HasA, Glucose, Molecular weight

  12. Purification of two high molecular weight proteases from rabbit reticulocyte lysate

    Hough, R.; Pratt, G.; Rechsteiner, M.

    1987-01-01

    The authors have purified two large proteases from rabbit reticulocyte lysate. The enzymes are so similar in their chromatographic behavior that each is the only significant contaminant of the other during the final stages of purification. At pH 7.8, both hydrolyze 125 I-α-casein and 4-methylcoumaryl-7-amide (MCA) derivatives with tyrosine, phenylalanine or arginine at the P 1 position. The larger, ATP-dependent enzyme degrades ubiquitin-lysozyme conjugates, but it does not degrade unmodified lysozyme. Hydrolysis of Suc-Leu-Leu-Val-Tyr-MCA by this enzyme is also stimulated two-fold in the presence of ATP. The protease has a molecular weight of 950,000 based on sedimentation, gel filtration and non-denaturing PAGE. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the protease is composed of a number of subunits with molecular masses between 32 and 110 kDa. Densitometric analysis showed equivalent amounts of the two larger chains, and the presence of one copy of each in the native enzyme would be consistent with an M/sub r/ of 950,000. The smaller protease has a molecular weight of 700,000 and is composed of 8 to 10 subunits ranging from 21,000 to 32,000. It cleaves ubiquitin-lysozyme conjugates only slightly, and hydrolysis of conjugates or fluorogenic peptide substrates is not stimulated by ATP. This protease appears similar, if not identical, to the multicatalytic protease complex first purified by Wilk and Orlowski

  13. Use of low molecular weight Heparin for Hemodialysis: A short term study

    Al-Arrayed, S.; Seshadri, R.

    2002-01-01

    Although unfractionated heparin (UFH) is the anticoagulant commonly usedfor Hemodialysis (HD), low molecular weight heparin (LMWH) has been found tobe equally efficacious. The aim of this study was to explore the safety andefficacy of a single bolus dose of the LMWH, enoxaparin. Thirty-eightpatients on maintenance HD were randomly divided into two equal groups. Themean age and body-weight of the two were comparable. While one group received1 mg/kg body-weight (the manufacturer's recommended dose) of enoxaparin forthree dialysis sessions of three-hour duration each, the either groupreceived a fixed dose of 40 mg for the same number of dialysis. For the nextthree dialysis sessions, these doses were exchanged between the groups. Inall, total of 228 HD sessions were monitored for clotting of bloodlines/dialyzers and bleeding from vascular access and other sites. The rateof complications was compared with the historical data while UFH was beingused for the same patients. In general, enoxapirin was associated with fewerepisodes of bleeding and clotting. Our study confirms that LMWH is ofcomparable efficacy to UFH and probably a lesser than recommended dose isadequate for three-hour HD session. (author)

  14. High Molecular Weight Glucan of the Culinary Medicinal Mushroom Agaricus bisporus is an α-Glucan that Forms Complexes with Low Molecular Weight Galactan

    Harry J. Wichers

    2010-08-01

    Full Text Available An a-glucan was isolated from the culinary medicinal mushroom A. bisporus by hot water extraction, ethanol precipitation and DEAE-cellulose chromatography. The resulting material showed a single HMW peak excluded from a Sephadex G50 column that could completely be degraded by α-amylase treatment. After heating in 1% SDS a small additional peak of low MW eluted from the G50 column. The monosaccharide composition of the main peak was evaluated by HPLC, and was found to consist of a majority of glucose (97.6%, and a minor proportion of galactose (2.4%. Methylation analysis and degradation by a-amylase indicated the presence of an a-glucan with a main chain consisting of (1®4-linked units, substituted at O-6 by α-D-glucopyranose single-units in the relation 1:8. Mono- (13C-, 1H-NMR and bidimensional [1H (obs.,13C-HSQC] spectroscopy analysis confirmed the a-configuration of the Glcp residues by low frequency resonances of C-1 at d 100.6, 100.2, and 98.8 ppm and H-1 high field ones at d 5.06, 5.11, and 4.74 ppm. The DEPT-13C-NMR allowed assigning the non-substituted and O-substituted –CH2 signals at d 60.3/60.8 and 66.2 ppm, respectively. Other assignments were attributed to C-2, C-3, C-4, C-5 and C-6 of the non-reducing ends at d 71.8; 72.8; 70.0; 71.3 and 60.3/60.8 ppm, respectively. The minor proportion of galactose that was demonstrated was probably derived from a complex between the a-glucan and a low molecular weight galactan.

  15. Molecular Weight Dependent Glucose Lowering Effect of Low Molecular Weight Chitosan Oligosaccharide (GO2KA1 on Postprandial Blood Glucose Level in SD Rats Model

    Emmanouil Apostolidis

    2013-07-01

    Full Text Available This research investigated the effect of enzymatically digested low molecular weight (MW chitosan oligosaccharide on type 2 diabetes prevention. Three different chitosan oligosaccharide samples with varying MW were evaluated in vitro for inhibition of rat small intestinal α-glucosidase and porcine pancreatic α-amylase (GO2KA1; 10,000 Da. The in vitro results showed that all tested samples had similar rat α-glucosidase inhibitory and porcine α-amylase inhibitory activity. Based on these observations, we decided to further investigate the effect of all three samples at a dose of 0.1 g/kg, on reducing postprandial blood glucose levels in Sprague-Dawley (SD rat model after sucrose loading test. In the animal trial, all tested samples had postprandial blood glucose reduction effect, when compared to control, however GO2KA1 supplementation had the strongest effect. The glucose peak (Cmax for GO2KA1 and control was 152 mg/dL and 193 mg/dL, respectively. The area under the blood glucose-time curve (AUC for GO2KA1 and control was 262 h mg/dL and 305 h mg/dL, respectively. Furthermore, the time of peak plasma concentration of blood glucose (Tmax for GO2KA1 was significantly delayed (0.9 h compared to control (0.5 h. These results suggest that GO2KA1 could have a beneficial effect for blood glucose management relevant to diabetes prevention in normal and pre-diabetic individuals. The suggested mechanism of action is via inhibition of the carbohydrate hydrolysis enzyme α-glucosidase and since GO2KA1 (MW < 1000 Da had higher in vivo effect, we hypothesize that it is more readily absorbed and might exert further biological effect once it is absorbed in the blood stream, relevant to blood glucose management.

  16. In Vivo Anti-Cancer Mechanism of Low-Molecular-Weight Fucosylated Chondroitin Sulfate (LFCS) from Sea Cucumber Cucumaria frondosa.

    Liu, Xiaoxiao; Liu, Yong; Hao, Jiejie; Zhao, Xiaoliang; Lang, Yinzhi; Fan, Fei; Cai, Chao; Li, Guoyun; Zhang, Lijuan; Yu, Guangli

    2016-05-12

    The low-molecular-weight fucosylated chondroitin sulfate (LFCS) was prepared from native fucosylated chondroitin sulfate (FCS), which was extracted and isolated from sea cucumber Cucumaria frondosa, and the anti-cancer mechanism of LFCS on mouse Lewis lung carcinoma (LLC) was investigated. The results showed that LFCS remarkably inhibited LLC growth and metastasis in a dose-dependent manner. LFCS induced cell cycle arrest by increasing p53/p21 expression and apoptosis through activation of caspase-3 activity in LLC cells. Meanwhile, LFCS suppressed the expression of vascular endothelial growth factor (VEGF), increased the expression of tissue inhibitor of metalloproteinase-1 (TIMP-1) and downregulated the matrix metalloproteinases (MMPs) level. Furthermore, LFCS significantly suppressed the activation of ERK1/2/p38 MAPK/NF-κB pathway, which played a prime role in expression of MMPs. All of these data indicate LFCS may be used as anti-cancer drug candidates and deserve further study.

  17. In Vivo Anti-Cancer Mechanism of Low-Molecular-Weight Fucosylated Chondroitin Sulfate (LFCS from Sea Cucumber Cucumaria frondosa

    Xiaoxiao Liu

    2016-05-01

    Full Text Available The low-molecular-weight fucosylated chondroitin sulfate (LFCS was prepared from native fucosylated chondroitin sulfate (FCS, which was extracted and isolated from sea cucumber Cucumaria frondosa, and the anti-cancer mechanism of LFCS on mouse Lewis lung carcinoma (LLC was investigated. The results showed that LFCS remarkably inhibited LLC growth and metastasis in a dose-dependent manner. LFCS induced cell cycle arrest by increasing p53/p21 expression and apoptosis through activation of caspase-3 activity in LLC cells. Meanwhile, LFCS suppressed the expression of vascular endothelial growth factor (VEGF, increased the expression of tissue inhibitor of metalloproteinase-1 (TIMP-1 and downregulated the matrix metalloproteinases (MMPs level. Furthermore, LFCS significantly suppressed the activation of ERK1/2/p38 MAPK/NF-κB pathway, which played a prime role in expression of MMPs. All of these data indicate LFCS may be used as anti-cancer drug candidates and deserve further study.

  18. Molecular weight evaluation of poly-dimethylsiloxane on solid surfaces using silver deposition/TOF-SIMS

    Inoue, Masae; Murase, Atsushi

    2004-06-01

    Molecular ions include information about end groups, functional groups and molecular weight. A method for directly detecting this in the high-mass region of the spectrum (>1000 amu) from poly-dimethylsiloxane (PDMS) on a solid surface was investigated. It was found that a TOF-SIMS analysis of silver-deposited surfaces (silver deposition/TOF-SIMS) is useful for this purpose. Two methods for silver deposition, the diode sputtering method and the vacuum evaporation coating method, were tried. The former required the sample to be cooled so as to prevent the damage of the sample surface due to thermal oxidation; the latter caused no damage to sample surfaces at room temperature. Using silver deposition/TOF-SIMS analysis, silver-cationized quasi-molecular ions were clearly detected from PDMS on solid surfaces and their images were observed without the interference of deposited silver. By applying to the analysis of paint defects, etc., it was confirmed that this technique is useful to analyze practical industrial materials. Silver-cationized ions were detected not only from PDMS, but also from other organic materials, such as some kinds of lubricant additives and fluorine oils on solid surfaces. Therefore, silver deposition/TOF-SIMS was proved to be useful for the analysis of thin substances on solid surfaces.

  19. Increased power to weight ratio of piezoelectric energy harvesters through integration of cellular honeycomb structures

    Chandrasekharan, N; Thompson, L L

    2016-01-01

    The limitations posed by batteries have compelled the need to investigate energy harvesting methods to power small electronic devices that require very low operational power. Vibration based energy harvesting methods with piezoelectric transduction in particular has been shown to possess potential towards energy harvesters replacing batteries. Current piezoelectric energy harvesters exhibit considerably lower power to weight ratio or specific power when compared to batteries the harvesters seek to replace. To attain the goal of battery-less self-sustainable device operation the power to weight ratio gap between piezoelectric energy harvesters and batteries need to be bridged. In this paper the potential of integrating lightweight honeycomb structures with existing piezoelectric device configurations (bimorph) towards achieving higher specific power is investigated. It is shown in this study that at low excitation frequency ranges, replacing the solid continuous substrate of conventional bimorph with honeycomb structures of the same material results in a significant increase in power to weight ratio of the piezoelectric harvester. At higher driving frequency ranges it is shown that unlike the traditional piezoelectric bimorph with solid continuous substrate, the honeycomb substrate bimorph can preserve optimum global design parameters through manipulation of honeycomb unit cell parameters. Increased operating lifetime and design flexibility of the honeycomb core piezoelectric bimorph is demonstrated as unit cell parameters of the honeycomb structures can be manipulated to alter mass and stiffness properties of the substrate, resulting in unit cell parameter significantly influencing power generation. (paper)

  20. Marsh plant response to metals: Exudation of aliphatic low molecular weight organic acids (ALMWOAs)

    Rocha, A. Cristina S.; Almeida, C. Marisa R.; Basto, M. Clara P.; Vasconcelos, M. Teresa S. D.

    2016-03-01

    Metal exposure is known to induce the production and secretion of substances, such as aliphatic low molecular weight organic acids (ALMWOAs), into the rhizosphere by plant roots. Knowledge on this matter is extensive for soil plants but still considerably scarce regarding marsh plants roots adapted to high salinity media. Phragmites australis and Halimione portulacoides, two marsh plants commonly distributed in European estuarine salt marshes, were used to assess the response of roots of both species, in terms of ALMWOAs exudation, to Cu, Ni and Cd exposure (isolated and in mixture since in natural environment, they are exposed to mixture of metals). As previous studies were carried out in unrealistic and synthetic media, here a more natural medium was selected. Therefore, in vitro experiments were carried out, with specimens of both marsh plants, and in freshwater contaminated with two different Cu, Ni and Cd concentrations (individual metal and in mixture). Both marsh plants were capable of liberating ALMWOAs into the surrounding medium. Oxalic, citric and maleic acids were found in P. australis root exudate solutions and oxalic and maleic acids in H. portulacoides root exudate solutions. ALMWOA liberation by both plants was plant species and metal-dependent. For instance, Cu affected the exudation of oxalic acid by H. portulacoides and of oxalic and citric acids by P. australis roots. In contrast, Ni and Cd did not stimulate any specific response. Regarding the combination of all metals, H. portulacoides showed a similar response to that observed for Cu individually. However, in the P. australis case, at high metal concentration mixture, a synergetic effect led to the increase of oxalic acid levels in root exudate solution and to a decrease of citric acid liberation. A correlation between ALMWOAs exudation and metal accumulation could not be established. P. australis and H. portulacoides are considered suitable metal phytoremediators of estuarine impacted areas

  1. Development of solvent-free offset ink using vegetable oil esters and high molecular-weight resin.

    Park, Jung Min; Kim, Young Han; Kim, Sung Bin

    2013-01-01

    In the development of solvent-free offset ink, the roles of resin molecular weight and used solvent on the ink performance were evaluated by examining the relationship between the various properties of resin and solvent and print quality. To find the best performing resin, the soy-oil fatty acid methyl ester (FAME) was applied to the five modified-phenolic resins having different molecular weights. It is found from the experimental results that the ink made of higher molecular weight and better solubility resin gives better printability and print quality. It is because larger molecular weight resin with better solubility gives higher rate of ink transfer. From the ink application of different esters to high molecular weight resin, the best printing performance was yielded from the soy-oil fatty acid butyl ester (FABE). It is due to its high kinematic viscosity resulting in the smallest change of ink transfer weight upon multiple number of printing, which improves the stability of ink quality.

  2. High dietary protein intake is associated with an increased body weight and total death risk.

    Hernández-Alonso, Pablo; Salas-Salvadó, Jordi; Ruiz-Canela, Miguel; Corella, Dolores; Estruch, Ramón; Fitó, Montserrat; Arós, Fernando; Gómez-Gracia, Enrique; Fiol, Miquel; Lapetra, José; Basora, Josep; Serra-Majem, Lluis; Muñoz, Miguel Ángel; Buil-Cosiales, Pilar; Saiz, Carmen; Bulló, Mònica

    2016-04-01

    High dietary protein diets are widely used to manage overweight and obesity. However, there is a lack of consensus about their long-term efficacy and safety. Therefore, the aim of this study was to assess the effect of long-term high-protein consumption on body weight changes and death outcomes in subjects at high cardiovascular risk. A secondary analysis of the PREDIMED trial was conducted. Dietary protein was assessed using a food-frequency questionnaire during the follow-up. Cox proportional hazard models were used to estimate the multivariate-adjusted hazard ratio (HR) and 95% confidence intervals (95%CI) for protein intake in relation to the risk of body weight and waist circumference changes, cardiovascular disease, cardiovascular death, cancer death and total death. Higher total protein intake, expressed as percentage of energy, was significantly associated with a greater risk of weight gain when protein replaced carbohydrates (HR: 1.90; 95%CI: 1.05, 3.46) but not when replaced fat (HR: 1.69; 95%CI: 0.94, 3.03). However, no association was found between protein intake and waist circumference. Contrary, higher total protein intake was associated with a greater risk of all-cause death in both carbohydrate and fat substitution models (HR: 1.59; 95%CI: 1.08, 2.35; and HR: 1.66; 95%CI: 1.13, 2.43, respectively). A higher consumption of animal protein was associated with an increased risk of fatal and non-fatal outcomes when protein substituted carbohydrates or fat. Higher dietary protein intake is associated with long-term increased risk of body weight gain and overall death in a Mediterranean population at high cardiovascular risk. Copyright © 2015 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  3. Effect of molecular weight and density of ambient gas on shock wave in laser-induced surface nanostructuring

    Guo Liying; Wang Xinwei

    2009-01-01

    This paper presents the results of molecular dynamics studies about the shock wave during laser-induced surface nanostructuring. A quasi-three dimensional model is constructed to study systems consisting of over 2 million atoms. Detailed studies are carried out about the shock wave front and Mach number, evolution of plume and ambient gas interaction zone, and energy exchange between the ambient gas and plume. Under an ambience of lower pressure or lighter molecular mass, the plume affects a larger area while the strength of the shock wave front is weaker. With the same ambient pressure, the ablated material features the same kinetic energy at the late stage regardless of the molecular weight of the ambient gas. The same conclusion holds for the energy increase of the ambient gas as well. When the ambient pressure is reduced, more kinetic energy is carried out by the ablated material while less energy is transferred to the ambient gas. It is observed that heavier ambient gas could bounce back the ablated material to the target surface.

  4. Synthesis and characterization of sugar based low molecular weight gelators and the preparation of chiral sulfinamides

    Mangunuru, Hari Prasad Reddy

    Low molecular weight gelators (LMWGs) have received considerable attention in the field of chemistry from last few decades. These compounds form self-assembled fibrous networks like micelles, cylindrical, sheets, fibers, layers and so on. The fibrous network entraps the solvent and forms gel, because of the self-assembly phenomenon and their demonstrated potential uses in a variety of areas, ranging from environmental to medicinal applications. Sugars are good starting materials to synthesize the new class of LMWG's, because these are different from some expensive materials, these are natural products. We have synthesized and characterized the LMGS's based on D-glucose and D-glucosamine. D-glucosamine is the versatile starting material to make different peptoids and triazoles. Several series of compounds were synthesized using compounds 1-3 as starting material and studied the gelation behavior all the compounds. We have studied the self-assembling properties of a new class of tripeptoids, synthesized by one-pot Ugi reaction from simple starting materials. Among the focused library of tripeptoids synthesized, we found that several efficient low molecular weight organogelators were obtained for aqueous DMSO and ethanol mixtures. We have also synthesized and characterized a series of monosaccharide triazole derivatives. These compounds were synthesized from N-acetyl glucosamine and D-glucose via a Cu(I) catalyzed azide/alkyne cycloaddition reaction (CuAAc). The compounds have been screened for their gelation properties and several efficient low molecular weight organo/hydro gelators were obtained, among these compounds, five per-acetyl glucosamine derivatives and one peracetyl glucose derivative were able to form gels in water. These new molecules are expected to be useful in drug delivery and tissue engineering.*. Asymmetric synthesis of chiral amines is a challenging in synthetic organic chemistry. The development of new catalysts for asymmetric organic

  5. Habitual Chocolate Consumption May Increase Body Weight in a Dose-Response Manner

    Greenberg, James A.; Buijsse, Brian

    2013-01-01

    Objective Habitual chocolate intake was recently found to be associated with lower body weight in three cross-sectional epidemiological studies. Our objective was to assess whether these cross-sectional results hold up in a more rigorous prospective analysis. Methods We used data from the Atherosclerosis Risk in Communities cohort. Usual dietary intake was assessed by questionnaire at baseline (1987–98), and after six years. Participants reported usual chocolate intake as the frequency of eating a 1-oz (∼28 g) serving. Body weight and height were measured at the two visits. Missing data were replaced by multiple imputation. Linear mixed-effects models were used to evaluate cross-sectional and prospective associations between chocolate intake and adiposity. Results Data were from 15,732 and 12,830 participants at the first and second visit, respectively. More frequent chocolate consumption was associated with a significantly greater prospective weight gain over time, in a dose-response manner. For instance, compared to participants who ate a chocolate serving less often than monthly, those who ate it 1–4 times a month and at least weekly experienced an increase in Body Mass Index (kg/m2) of 0.26 (95% CI 0.08, 0.44) and 0.39 (0.23, 0.55), respectively, during the six-year study period. In cross-sectional analyses the frequency of chocolate consumption was inversely associated with body weight. This inverse association was attenuated after excluding participants with preexisting obesity-related illness. Compared to participants without such illness, those with it had higher BMI and reported less frequent chocolate intake, lower caloric intake, and diets richer in fruits and vegetables. They tended to make these dietary changes after becoming ill. Conclusions Our prospective analysis found that a chocolate habit was associated with long-term weight gain, in a dose-response manner. Our cross-sectional finding that chocolate intake was associated with lower body

  6. Habitual chocolate consumption may increase body weight in a dose-response manner.

    Greenberg, James A; Buijsse, Brian

    2013-01-01

    Habitual chocolate intake was recently found to be associated with lower body weight in three cross-sectional epidemiological studies. Our objective was to assess whether these cross-sectional results hold up in a more rigorous prospective analysis. We used data from the Atherosclerosis Risk in Communities cohort. Usual dietary intake was assessed by questionnaire at baseline (1987-98), and after six years. Participants reported usual chocolate intake as the frequency of eating a 1-oz (~28 g) serving. Body weight and height were measured at the two visits. Missing data were replaced by multiple imputation. Linear mixed-effects models were used to evaluate cross-sectional and prospective associations between chocolate intake and adiposity. Data were from 15,732 and 12,830 participants at the first and second visit, respectively. More frequent chocolate consumption was associated with a significantly greater prospective weight gain over time, in a dose-response manner. For instance, compared to participants who ate a chocolate serving less often than monthly, those who ate it 1-4 times a month and at least weekly experienced an increase in Body Mass Index (kg/m2) of 0.26 (95% CI 0.08, 0.44) and 0.39 (0.23, 0.55), respectively, during the six-year study period. In cross-sectional analyses the frequency of chocolate consumption was inversely associated with body weight. This inverse association was attenuated after excluding participants with preexisting obesity-related illness. Compared to participants without such illness, those with it had higher BMI and reported less frequent chocolate intake, lower caloric intake, and diets richer in fruits and vegetables. They tended to make these dietary changes after becoming ill. Our prospective analysis found that a chocolate habit was associated with long-term weight gain, in a dose-response manner. Our cross-sectional finding that chocolate intake was associated with lower body weight did not apply to participants without

  7. Habitual chocolate consumption may increase body weight in a dose-response manner.

    James A Greenberg

    Full Text Available OBJECTIVE: Habitual chocolate intake was recently found to be associated with lower body weight in three cross-sectional epidemiological studies. Our objective was to assess whether these cross-sectional results hold up in a more rigorous prospective analysis. METHODS: We used data from the Atherosclerosis Risk in Communities cohort. Usual dietary intake was assessed by questionnaire at baseline (1987-98, and after six years. Participants reported usual chocolate intake as the frequency of eating a 1-oz (~28 g serving. Body weight and height were measured at the two visits. Missing data were replaced by multiple imputation. Linear mixed-effects models were used to evaluate cross-sectional and prospective associations between chocolate intake and adiposity. RESULTS: Data were from 15,732 and 12,830 participants at the first and second visit, respectively. More frequent chocolate consumption was associated with a significantly greater prospective weight gain over time, in a dose-response manner. For instance, compared to participants who ate a chocolate serving less often than monthly, those who ate it 1-4 times a month and at least weekly experienced an increase in Body Mass Index (kg/m2 of 0.26 (95% CI 0.08, 0.44 and 0.39 (0.23, 0.55, respectively, during the six-year study period. In cross-sectional analyses the frequency of chocolate consumption was inversely associated with body weight. This inverse association was attenuated after excluding participants with preexisting obesity-related illness. Compared to participants without such illness, those with it had higher BMI and reported less frequent chocolate intake, lower caloric intake, and diets richer in fruits and vegetables. They tended to make these dietary changes after becoming ill. CONCLUSIONS: Our prospective analysis found that a chocolate habit was associated with long-term weight gain, in a dose-response manner. Our cross-sectional finding that chocolate intake was associated with

  8. Ballistic behavior of ultra-high molecular weight polyethylene composite: effect of gamma radiation

    Alves, Andreia L. dos Santos; Nascimento, Lucio F.C.; Suarez, Joao C. Miguez; lucio2002bol.com.br

    2003-01-01

    Since World War II, textile composites have been used as ballistic armor. Ultra-high molecular weight polyethylene (UHMWPE) fibers are used in the production of armor materials. As they have been developed and commercialized only recently, there is not enough information about the effect of environmental agents in the ballistic performance of UHMWPE composites. In the present work, was evaluated the ballistic behavior of composite plates manufactured with UHMWPE fibers after exposure to gamma radiation. The ballistic tests results were related to the macromolecular alterations induced by the radiation through mechanical (hardness, impact and flexure) and physicochemical (Ftir/Mir. DSC and TGA) testing. It was observed that irradiation induces changes in the UHMWPE, degrading the ballistic performance of the composite. These results are presented and discussed. (author)

  9. Microstructure, molecular weight and thermal behavior of natural rubber (NR) from mangabeira (Hancornia speciosa)

    Santos, Expedito Flavio dos; Feitosa, Judith P.A.; Ricardo, Nagila M.P.S.

    2001-01-01

    The natural rubber (NR) from Hancornia speciosa contains characteristics that turns it a good alternative in elastomers supply. The NMR and IR spectra showed that the rubber of mangabeira is composed fundamentally by poly(1,4-cis-isoprene). The rubber molecular weight obtained by GPC and viscometry was 2,0x10 6 and 1,3x10 6 g/mol, respectively, in good agreement with the values determined for seringueira and manicoba NR. The glass transition temperature obtained by DSC (Tg = - 65 deg C) showed the mangabeira rubber is ideal to be utilized in regions of cold climate without compromising its mechanical properties. The rubber has also good thermal stability up to 213 deg C, as indicated by TG curves. This results indicated that the mangabeira NR can be effectively used in vulcanized articles or to be added to asphalt. (author)

  10. Low molecular weight polylactic acid as a matrix for the delayed release of pesticides.

    Zhao, Jing; Wilkins, Richard M

    2005-05-18

    Low molecular weight polylactic acid (LMW PLA) was used as a matrix to formulate biodegradable matrix granules and films with bromacil using a melt process. The compatibility of the PLA with bromacil was evaluated. The release characteristics of the formulations were investigated in vitro. The degradation and erosion of the formulations were monitored by pH and gravimetric analysis during the course of release. Various granules and films had similar biphasic release patterns, a delayed release followed by an explosive release. The release rates were independent of bromacil content in the matrix, but varied with the geometry of matrices. The mechanisms of diffusion and erosion were involved in the release. The delayed release of the formulations was dominantly governed by the degradation and erosion of PLA. LMW PLA underwent bulk erosion. LMW PLA-based matrix formulations could thus be useful for the application of pesticides to sensitive targets such as seed treatment.

  11. Low molecular weight heparins in the prevention of deep-vein thrombosis in general surgery.

    Breddin, H K

    1999-01-01

    Unfractionated heparin (UFH) was the established treatment in the early 1980s for the prophylaxis of venous thromboembolic disease (VTED) in patients undergoing general surgery. This was one of the earliest indications in which low molecular weight heparins (LMWHs) were tested, and about 40 trials have revealed that these agents are at least as effective and safe as UFH with a tendency of superiority when higher dosages are used. In most trials, the fibrinogen uptake test has been used to assess the frequency of deep vein thrombosis. LMWHs exhibit a number of improved features over UFH, including ease of administration and convenient once daily dosing, facilitating outpatient management. A still open question is the ideal time and dose of the first one or two injections of a LMWH. To determine the clinical relevance of product differentiation further, clinical trials, directly comparing different LMWHs, are required.

  12. Determination of nanoparticle size distribution together with density or molecular weight by 2D analytical ultracentrifugation

    Carney, Randy P.; Kim, Jin Young; Qian, Huifeng; Jin, Rongchao; Mehenni, Hakim; Stellacci, Francesco; Bakr, Osman

    2011-01-01

    Nanoparticles are finding many research and industrial applications, yet their characterization remains a challenge. Their cores are often polydisperse and coated by a stabilizing shell that varies in size and composition. No single technique can characterize both the size distribution and the nature of the shell. Advances in analytical ultracentrifugation allow for the extraction of the sedimentation (s) and diffusion coefficients (D). Here we report an approach to transform the s and D distributions of nanoparticles in solution into precise molecular weight (M), density (?P) and particle diameter (dp) distributions. M for mixtures of discrete nanocrystals is found within 4% of the known quantities. The accuracy and the density information we achieve on nanoparticles are unparalleled. A single experimental run is sufficient for full nanoparticle characterization, without the need for standards or other auxiliary measurements. We believe that our method is of general applicability and we discuss its limitations. 2011 Macmillan Publishers Limited. All rights reserved.

  13. Toxicological Evaluation of Low Molecular Weight Fucoidan in Vitro and in Vivo

    Pai-An Hwang

    2016-06-01

    Full Text Available For a long time, fucoidan has been well known for its pharmacological activities, and recently low molecular weight fucoidan (LMF has been used in food supplements and pharmaceutical products. In the present study, LMF was extracted from Laminaria japonica by enzyme hydrolysis. The toxicity of LMF in mouse and rat models was determined by many methods, such as total arsenic content, bacterial reverse mutation assay, chromosome aberration assay, and in vivo micronucleus assay. The present findings showed that LMF at 5000 μg/mL exhibited no mutagenicity. It also produced no formatting disruption of red blood cells in vivo. At 2000 mg/kg BW/day there were no toxicological indications. LMF is expected to be used as a safe food supplement.

  14. Reversible Masking Using Low-Molecular-Weight Neutral Lipids to Achieve Optimal-Targeted Delivery

    Nancy Smyth Templeton

    2012-01-01

    Full Text Available Intravenous injection of therapeutics is required to effectively treat or cure metastatic cancer, certain cardiovascular diseases, and other acquired or inherited diseases. Using this route of delivery allows potential uptake in all disease targets that are accessed by the bloodstream. However, normal tissues and organs also have the potential for uptake of therapeutic agents. Therefore, investigators have used targeted delivery to attempt delivery solely to the target cells; however, use of ligands on the surface of delivery vehicles to target specific cell surface receptors is not sufficient to avoid nonspecific uptake. PEGylation has been used for decades to try to avoid nonspecific uptake but suffers from many problems known as “The PEGylation Dilemma.” We have solved this dilemma by replacing PEGylation with reversible masking using low-molecular-weight neutral lipids in order to achieve optimal-targeted delivery solely to target cells. Our paper will focus on this topic.

  15. Determination of free inositols and other low molecular weight carbohydrates in vegetables.

    Hernández-Hernández, Oswaldo; Ruiz-Aceituno, Laura; Sanz, María Luz; Martínez-Castro, Isabel

    2011-03-23

    Different low molecular weight carbohydrates including saccharides, polyalcohols, sugar acids, and glycosides have been identified and quantified in different edible vegetables from Asteraceae, Amarantaceae, Amarylidaceae, Brassicaceae, Dioscoreaceae, and Solanaceae families by gas chromatography-mass spectrometry. Apart from glucose, fructose, and sucrose, other saccharides such as sedoheptulose in chicory, spinach, cabbage, purple yam, eggplant, radish, and oak leaf lettuce, rutinose in eggplant skin, and a glycosyl-inositol in spinach have been identified. chiro-Inositol was found in all vegetables of the Asteraceae family (3.1-32.6 mg 100 g(-1)), whereas scyllo-inositol was detected in those of purple yam, eggplant, artichoke, chicory, escarole, and endive (traces-23.2 mg 100 g(-1)). α-Galactosides, kestose, glucaric acid, and glycosyl-glycerols were also identified and quantified in some of the analyzed vegetables. Considering the bioactivity of most of these compounds, mainly chicory leaves, artichokes, lettuces, and purple yam could constitute beneficial sources for human health.

  16. Diffusion of hydrogen, hydrogen sulfide and large molecular weight anions in bentonite

    Eriksen, T.E.; Jacobsson, A.

    1982-01-01

    The diffusivities of HS - and H 2 have been determined from profile analysis and steady state transport experiments. The diffusivity of HS - was found to be 9x10 - 12 and 4x10xsec 1 in MX-80 and Erbsloeh bentonite respectively. The results are in fair agreement with the results earlier obtained for Cl - and I - . The H 2 diffusivity calculated from steady state transport was found to be surprisingly low (3.6x10 - 12 m 2 xsec - 1 ). Various heavy anions with molecular weights 290-30x10 3 were found to migrate through MX-80 bentonite with diffusivities in the range (2,1-0,75)x10 - 15 m 2 xsec - 1 . (Author)

  17. Prolonged thromboprophylaxis with low molecular weight heparin for abdominal or pelvic surgery

    Rasmussen, Morten Schnack; Jørgensen, Lars Nannestad; Wille-Jørgensen, Peer

    2009-01-01

    BACKGROUND: Major abdominal and pelvic surgery carries a high risk of venous thromboembolism (VTE). The efficacy of thromboprophylaxis with low-molecular weight heparin (LMWH) administered during the in-hospital period is well documented, but the optimal duration of thromboprophylaxis after surgery...... evaluating prolonged thromboprophylaxis with LMWH as compared to control or placebo. 133 studies were found in the searches, of which only 4 were found eligible for inclusion, and 129 were excluded. The incidence of overall VTE after major abdominal or pelvic surgery was 14.3% (95% confidence interval 11...... significant reduction of even the incidence of symptomatic VTE from 1.7% (95% CI 0.8% - 3.4%) in the control group to 0.2 % (95% CI 0.0% - 1.2%) in patients receiving prolonged thromboprophylaxis, Peto Odds ratio 0.22 (95% CI 0.06 -0.80), P = 0.02. The respective incidence of bleeding in the control and LMWH...

  18. Spontaneous Hemocholecyst in an End-Stage Renal Failure Patient on Low Molecular Weight Heparin Hemodialysis

    Konstantinos Blouhos

    2012-01-01

    Full Text Available The present paper describes a case of spontaneous hemocholecyst in a patient with end-stage renal failure on low molecular weight heparin hemodialysis. The patient presented with acute right upper quadrant pain. An initial ultrasound scan demonstrated a distended gallbladder containing echogenic bile without stones. During hospitalization the patient became febrile, and jaundiced, developed leukocytosis, and had an elevation in serum bilirubin, transaminases, and alkaline phosphatase. A new ultrasound demonstrated a thick-walled gallbladder containing echogenic bile and pericholecystic fluid. MRI depicted a distended gallbladder containing material of mixed signal intensity and a normal biliary tract. Open cholecystectomy revealed a gallbladder filled with blood and clots, and transcystic common bile duct exploration flushed blood clots out of the bile duct. To our knowledge this is the second case of spontaneous hemocholecyst reported in the literature as a consequence of uremic bleeding and LMWH hemodialysis in the absence of other pathology.

  19. Determination of nanoparticle size distribution together with density or molecular weight by 2D analytical ultracentrifugation

    Carney, Randy P.

    2011-06-07

    Nanoparticles are finding many research and industrial applications, yet their characterization remains a challenge. Their cores are often polydisperse and coated by a stabilizing shell that varies in size and composition. No single technique can characterize both the size distribution and the nature of the shell. Advances in analytical ultracentrifugation allow for the extraction of the sedimentation (s) and diffusion coefficients (D). Here we report an approach to transform the s and D distributions of nanoparticles in solution into precise molecular weight (M), density (?P) and particle diameter (dp) distributions. M for mixtures of discrete nanocrystals is found within 4% of the known quantities. The accuracy and the density information we achieve on nanoparticles are unparalleled. A single experimental run is sufficient for full nanoparticle characterization, without the need for standards or other auxiliary measurements. We believe that our method is of general applicability and we discuss its limitations. 2011 Macmillan Publishers Limited. All rights reserved.

  20. Supramolecular Structure and Mechanical Characteristics of Ultrahigh-Molecular-Weight Polyethylene-Inorganic Nanoparticle Nanocomposites

    Okhlopkova, T. A.; Borisova, R. V.; Nikiforov, L. A.; Spiridonov, A. M.; Okhlopkova, A. A.; Cho, Jin-Ho; Jeong, Dae-Yong

    2016-01-01

    We investigated the mechanical properties and structure of polymeric nanocomposites (PNCs) with anultrahigh-molecular-weight polyethylene (UHMWPE) matrix and aluminum and silicon oxide and nitride nanoparticle (NP) fillers. Mixing with a paddle mixer or by joint mechanical activation in a planetary mill was used for the PNC preparation. Joint mechanical activation afforded PNCs with better mechanical properties than paddle mixing. Scanning electron microscopy suggested that the poorer mechanical properties can be attributed to the disordered regions and imperfect spherulites in the PNC supramolecular structure arising from paddle mixing. The better mechanical properties observed with joint mechanical activation may derive from the uniform NP distribution in the polymer matrix and absence of disordered regions.

  1. Skin: Major target organ of allergic reactions to small molecular weight compounds

    Merk, Hans F.; Baron, Jens M.; Neis, Mark M.; Obrigkeit, Daniela Hoeller; Karlberg, Ann-Therese

    2007-01-01

    Skin is a major target organ for allergic reactions to small molecular weight compounds. Drug allergic reactions may be life-threatening such as in the case of anaphylactic reactions or bullous drug reactions and occur in about 5% of all hospitalized patients. Allergic contact dermatitis has an enormous influence on the social life of the patient because it is the most frequent reason for occupational skin diseases and the treatment and prevention of this disease cost approximately Euro 3 billion per year in Germany. The different proposed pathophysiological pathways leading to a drug eruption are discussed in this paper. All major enzymes which are involved in the metabolism of xenobiotica were shown to be present in skin. Evidence supporting the role of metabolism in the development of drug allergy and allergic contact dermatitis is demonstrated in the example of sulphonamides and fragrances

  2. Electrophoretic variation in low molecular weight lens crystallins from inbred strains of rats.

    Donner, M E; Skow, L C; Kunz, H W; Gill, T J

    1985-10-01

    Analysis of rat lens soluble proteins by analytical isoelectric focusing detected two inherited electrophoretic differences in low molecular weight (LM) crystallins from inbred strains of rats (Rattus norvegicus). The polymorphic lens crystallins were shown to be similar to a genetically variant LM crystallin, LEN-1, previously described in mice (Mus musculus) and encoded on chromosome 1, at a locus linked to Pep-3 (dipeptidase). Linkage analysis demonstrated that the rat crystallin locus was loosely linked to Pep-3 at a recombination distance of 38 +/- 4.5 U. These data suggest the conservation of a large chromosomal region during the evolution of Rodentia and support the hypothesis that the gamma-crystallins are evolving more rapidly than alpha- or beta-crystallins.

  3. Possible hypoglycemic effect of Aloe vera L. high molecular weight fractions on type 2 diabetic patients

    Yagi, Akira; Hegazy, Sahar; Kabbash, Amal; Wahab, Engy Abd-El

    2009-01-01

    Aloe vera L. high molecular weight fractions (AHM) containing less than 10 ppm of barbaloin and polysaccharide (MW: 1000 kDa) with glycoprotein, verectin (MW: 29 kDa), were prepared by patented hyper-dry system in combination of freeze–dry technique with microwave and far infrared radiation. AHM produced significant decrease in blood glucose level sustained for 6 weeks of the start of the study. Significant decrease in triglycerides was only observed 4 weeks after treatment and continued thereafter. No deterious effects on kidney and liver functions were apparent. Treatment of diabetic patients with AHM may relief vascular complications probably via activation of immunosystem. PMID:23964163

  4. Sharp Absorption Peaks in THz Spectra Valuable for Crystal Quality Evaluation of Middle Molecular Weight Pharmaceuticals

    Sasaki, Tetsuo; Sakamoto, Tomoaki; Otsuka, Makoto

    2018-05-01

    Middle molecular weight (MMW) pharmaceuticals (MW 400 4000) are attracting attention for their possible use in new medications. Sharp absorption peaks were observed in MMW pharmaceuticals at low temperatures by measuring with a high-resolution terahertz (THz) spectrometer. As examples, high-resolution THz spectra for amoxicillin trihydrate, atorvastatin calcium trihydrate, probucol, and α,β,γ,δ-tetrakis(1-methylpyridinium-4-yl)porphyrin p-toluenesulfonate (TMPyP) were obtained at 10 K. Typically observed as peaks with full width at half-height (FWHM) values as low as 5.639 GHz at 0.96492 THz in amoxicillin trihydrate and 8.857 GHz at 1.07974 THz for probucol, many sharp peaks of MMW pharmaceuticals could be observed. Such narrow absorption peaks enable evaluation of the crystal quality of MMW pharmaceuticals and afford sensitive detection of impurities.

  5. Characterization of Low-Molecular-Weight Heparins by Strong Anion-Exchange Chromatography.

    Sadowski, Radosław; Gadzała-Kopciuch, Renata; Kowalkowski, Tomasz; Widomski, Paweł; Jujeczka, Ludwik; Buszewski, Bogusław

    2017-11-01

    Currently, detailed structural characterization of low-molecular-weight heparin (LMWH) products is an analytical subject of great interest. In this work, we carried out a comprehensive structural analysis of LMWHs and applied a modified pharmacopeial method, as well as methods developed by other researchers, to the analysis of novel biosimilar LMWH products; and, for the first time, compared the qualitative and quantitative composition of commercially available drugs (enoxaparin, nadroparin, and dalteparin). For this purpose, we used strong anion-exchange (SAX) chromatography with spectrophotometric detection because this method is more helpful, easier, and faster than other separation techniques for the detailed disaccharide analysis of new LMWH drugs. In addition, we subjected the obtained results to statistical analysis (factor analysis, t-test, and Newman-Keuls post hoc test).

  6. Low-molecular-weight cyclin E: the missing link between biology and clinical outcome

    Akli, Said; Keyomarsi, Khandan

    2004-01-01

    Cyclin E, a key mediator of transition during the G 1 /S cellular division phase, is deregulated in a wide variety of human cancers. Our group recently reported that overexpression and generation of low-molecular-weight (LMW) isoforms of cyclin E were associated with poor clinical outcome among breast cancer patients. However, the link between LMW cyclin E biology in mediating a tumorigenic phenotype and clinical outcome is unknown. To address this gap in knowledge, we assessed the role of LMW isoforms in breast cancer cells; we found that these forms of cyclin E induced genomic instability and resistance to p21, p27, and antiestrogens in breast cancer. These findings suggest that high levels of LMW isoforms of cyclin E not only can predict failure to endocrine therapy but also are true prognostic indicators because of their influence on cell proliferation and genetic instability

  7. Physicochemical and immunologic characterization of low-molecular-weight allergoids of Dactylis glomerata pollen proteins.

    Cirković, T D; Bukilica, M N; Gavrović, M D; Vujcić, Z M; Petrović, S; Jankov, R M

    1999-02-01

    Orchard grass (Dactylis glomerata) pollen proteins were chemically modified by means of acid anhydrides (maleic and succinic anhydride) to obtain low-molecular-weight allergoids. Chemical modification in both cases led to the replacement of one positive charge (epsilon amino group of Lys) by one negative charge, yielding proteins with changed physicochemical properties in comparison to the native orchard grass-pollen proteins. Physicochemical characterization of derivatives was done by gel chromatography, SDS-PAGE, and isoelectric focusing. To examine the IgE-binding properties of these derivatives, we carried out immunoblotting. To examine the ability of derivatives to induce IgG production, we immunized rabbits. Skin prick testing with the allergoids was performed on 15 individuals allergic to orchard grass pollens and on two healthy subjects. It was shown that the modified proteins retain their original molecular weights, but change pI to more acidic values. In the case of allergoids, a strong reduction in IgE binding was found. Immunization of rabbits with allergoids showed that the derivatives retain the ability to induce IgG production, and that the antisera obtained in such a way react to native (unmodified) extract. The ability of derivatives to induce allergic reaction was significantly reduced. The patients (86.6%) included in our study exhibited less than 50% of native extract response. Among them, 53.3% had no response to one or both allergoids. These modification procedures yield allergoids with a reduced allergenic activity and preserved immunogenic potential suitable for use in immunotherapy.

  8. The association of low-molecular-weight hydrophobic compounds with native casein micelles in bovine milk.

    Cheema, M; Mohan, M S; Campagna, S R; Jurat-Fuentes, J L; Harte, F M

    2015-08-01

    The agreed biological function of the casein micelles in milk is to carry minerals (calcium, magnesium, and phosphorus) from mother to young along with amino acids for growth and development. Recently, native and modified casein micelles were used as encapsulating and delivery agents for various hydrophobic low-molecular-weight probes. The ability of modified casein micelles to bind certain probes may derive from the binding affinity of native casein micelles. Hence, a study with milk from single cows was conducted to further elucidate the association of hydrophobic molecules into native casein micelles and further understand their biological function. Hydrophobic and hydrophilic extraction followed by ultraperformance liquid chromatography-high resolution mass spectrometry analysis were performed over protein fractions obtained from size exclusion fractionation of raw skim milk. Hydrophobic compounds, including phosphatidylcholine, lyso-phosphatidylcholine, phosphatidylethanolamine, and sphingomyelin, showed strong association exclusively to casein micelles as compared with whey proteins, whereas hydrophilic compounds did not display any preference for their association among milk proteins. Further analysis using liquid chromatography-tandem mass spectrometry detected 42 compounds associated solely with the casein-micelles fraction. Mass fragments in tandem mass spectrometry identified 4 of these compounds as phosphatidylcholine with fatty acid composition of 16:0/18:1, 14:0/16:0, 16:0/16:0, and 18:1/18:0. These results support that transporting low-molecular-weight hydrophobic molecules is also a biological function of the casein micelles in milk. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  9. Characterization of high molecular weight cadmium species in contaminated vegetable food

    Guenther, K.; Kastenholz, B. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Chemie und Dynamik der Geosphaere 7: Angewandte Physikalische Chemie; Ji, G. [Bonn Univ. (Germany). Lehrstuhl fuer Lebensmittelwissenschaft und Lebensmittelchemie

    2000-10-01

    Spinach and radish grown from seeds were each contaminated with 4 different amounts of cadmium. After a cell breakdown of the eatable parts and centrifugation of the resulting homogenates all supernatants (cytosols) were separated by gel permeation chromatography (GPC). The size-range of the GPC method used was about 20-8000 kDa for globular proteins. The high molecular weight (HMW-Cd-SP, 150-700 kDa) and the low molecular weight Cd species (LMW-Cd-SP, < 150 kDa) in all plant cytosols eluted at about the same retention volume by GPC. The most important Cd binding form in the cytosols of all plants was found to be HMW-Cd-SP. The Cd elution maxima were detected in the range of about 200 kDa. The Cd determinations were performed with ET-AAS by means of matrix modifier. By incubating chosen cytosols with a proteinase before the GPC it was verified that the HMW-Cd-SP in both vegetables are Cd proteins. The molar proportions protein/Cd were about 2-6 in the respective GPC fractions of the HMW-Cd-SP of the highest contaminated plants. The GPC fractions of the HMW-Cd-SP of spinach and radish were further separated by a preparative, native and continuous polyacrylamide gel electrophoresis (PAGE) method. At pH 8 the species were negatively charged, had only a small UV-absorption at 280 nm and showed a very similar elution behavior in all analyzed cytosols. Therefore, we suppose that the HMW-Cd-SP of these two different vegetable foodstuffs have a very similar chemical structure. (orig.)

  10. High molecular weight of polysaccharides from Hericium erinaceus against amyloid beta-induced neurotoxicity.

    Cheng, Jai-Hong; Tsai, Chia-Ling; Lien, Yi-Yang; Lee, Meng-Shiou; Sheu, Shyang-Chwen

    2016-06-07

    Hericium erinaceus (HE) is a well-known mushroom in traditional Chinese food and medicine. HE extracts from the fruiting body and mycelia not only exhibit immunomodulatory, antimutagenic and antitumor activity but also have neuroprotective properties. Here, we purified HE polysaccharides (HEPS), composed of two high molecular weight polysaccharides (1.7 × 10(5) Da and 1.1 × 10(5) Da), and evaluated their protective effects on amyloid beta (Aβ)-induced neurotoxicity in rat pheochromocytoma PC12 cells. HEPS were prepared and purified using a 95 % ethanol extraction method. The components of HEPS were analyzed and the molecular weights of the polysaccharides were determined using high-pressure liquid chromatography (HPLC). The neuroprotective effects of the polysaccharides were evaluated through a 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and an MTT assay and by quantifying reactive oxygen species (ROS) and mitochondrial membrane potentials (MMP) of Aβ-induced neurotoxicity in cells. Our results showed that 250 μg/ml HEPS was harmless and promoted cell viability with 1.2 μM Aβ treatment. We observed that the free radical scavenging rate exceeded 90 % when the concentration of HEPS was higher than 1 mg/mL in cells. The HEPS decreased the production of ROS from 80 to 58 % in a dose-dependent manner. Cell pretreatment with 250 μg/mL HEPS significantly reduced Aβ-induced high MMPs from 74 to 51 % and 94 to 62 % at 24 and 48 h, respectively. Finally, 250 μg/mL of HEPS prevented Aβ-induced cell shrinkage and nuclear degradation of PC12 cells. Our results demonstrate that HEPS exhibit antioxidant and neuroprotective effects on Aβ-induced neurotoxicity in neurons.

  11. Investigation of tribological properties of graphene oxide reinforced ultrahigh molecular weight polyethylene under artificial seawater lubricating condition

    Pang, Wenchao; Ni, Zifeng; Wu, JiaLiang; Zhao, Yongwu

    2018-03-01

    A range of ultrahigh molecular weight polyethylene (UHMWPE)/graphene oxide (GO) nanocomposites were fabricated using liquid-phase ultrasonication mixing followed by hot-pressing. The wettability, water absorption and corrosion resistance of composites were studied to prove the composites were suitable for application in liquid environment. The tribological properties of composites under dry, deionized water and seawater lubricating condition were investigated. The results showed that the incorporation of GO decreased the wear rate of UHMWPE under different lubricating conditions and with the increase of GO addition, the wear rate of UHMWPE/GO composites decreased. UHMWPE/GO composites exhibited better tribological behaviors under seawater lubricating condition than other conditions, because good corrosion resistance and excellent wear resistance of UHMWPE/GO composites, and the lubricating effect of seawater is also indispensable.

  12. Studies on the oligosaccharide heterogeneity of the isoelectric forms of the lower molecular weight acid phosphatase of frog liver.

    Kubicz, A; Szalewicz, A; Chrambach, A

    1991-01-01

    1. The lower molecular weight, heterogeneous acid phosphatase (AcPase) from the frog liver (Rana esculenta) containing AcPase I, II, III and IV was separated into enzymatically active components by isoelectric focusing in an immobilized pH gradient. 2. The blotted enzyme bands were characterized by their different binding patterns obtained with the lectins concanavalin A, wheat germ agglutinin (WGA), Lens culinaris hemagglutinin (LcH) and peanut agglutinin (PNA). 3. In situ neuraminidase treatment reduced the staining intensity of some WGA-bands and increased that of PNA-bands. 4. The finding that AcPases I, II, III and IV differ in their carbohydrate chain composition, together with previous results showing different bioactivities of AcPases III and IV, indicates a correlation between the glycosylation state of enzyme forms and their physiological action.

  13. Water extraction of coals - potential for estimating low molecular weight organic acids as carbon feedstock for the deep terrestrial biosphere

    Vieth, A.; Mangelsdorf, K.; Sykes, R.; Horsfield, B. [Geoforschungszentrum Potsdam, Potsdam (Germany)

    2008-08-15

    With the recent increasing interest in the deep biosphere, the question arises as to where the carbon sources that support deep microbial communities are derived from. Our research was focussed on the water-soluble, low molecular weight (LMW) organic acids that are potentially available from different sedimentary lithologies to serve as a carbon source to feed the deep biosphere. A series of Eocene-Pleistocene coals, mudstones and sandstones of varying rank (maturity) and total organic carbon (TOC) content from the Waikato Basin, New Zealand, has been Soxhlet-extracted using water. The combined concentration of recovered formate, acetate and oxalate range from 366 to 2499 {mu} g/g sediment and appear to be dependent on rank, organofacies and TOC. The yields indicate the potential of carbonaceous sediments to feed the local deep terrestrial biosphere over geological periods of time. The existence of living microbial organisms in the mudstones and sandstones was proved by the identification of intact phospholipids (PLs).

  14. Purification of High Molecular Weight Genomic DNA from Powdery Mildew for Long-Read Sequencing.

    Feehan, Joanna M; Scheibel, Katherine E; Bourras, Salim; Underwood, William; Keller, Beat; Somerville, Shauna C

    2017-03-31

    The powdery mildew fungi are a group of economically important fungal plant pathogens. Relatively little is known about the molecular biology and genetics of these pathogens, in part due to a lack of well-developed genetic and genomic resources. These organisms have large, repetitive genomes, which have made genome sequencing and assembly prohibitively difficult. Here, we describe methods for the collection, extraction, purification and quality control assessment of high molecular weight genomic DNA from one powdery mildew species, Golovinomyces cichoracearum. The protocol described includes mechanical disruption of spores followed by an optimized phenol/chloroform genomic DNA extraction. A typical yield was 7 µg DNA per 150 mg conidia. The genomic DNA that is isolated using this procedure is suitable for long-read sequencing (i.e., > 48.5 kbp). Quality control measures to ensure the size, yield, and purity of the genomic DNA are also described in this method. Sequencing of the genomic DNA of the quality described here will allow for the assembly and comparison of multiple powdery mildew genomes, which in turn will lead to a better understanding and improved control of this agricultural pathogen.

  15. EFFECT OF MOLECULAR WEIGHT ON THE YIELD BEHAVIOUR OF EPY EPOXY COMPOUND

    Magdalena Urbaniak

    2016-12-01

    Full Text Available A series of epoxy networks with molecular weight between crosslinks (Mc ranging from 117 to 508 g/mol were investigated by employing as DSC and DMA methods and compression testing over a broad range of test temperatures (from 20 to 120 °C and strain rates (from 0.0208 to 20.8 min–1. Mechanical characteristics vs. testing temperature and strain rate developed in relation to working conditions of EPY compound applied for machine foundation chocks as well as effect of crosslinking on glass transition temperature (Tg presented in this paper let to find out the effect of molecular architecture composed chiefly by Mc on the thermal and mechanical properties that govern yield behaviour of the material. The investigations carried out in a.m. ranges of testing temperatures and strain rates showed that whichever change of Mc is related to the change in crosslink density causing relative shift in the Tg of the compound. However, a sensitivity of the polymer material on changes in strain rate falls down with growth of testing temperature. Obtained results prove that yielding in EPY compound can be examined in categories of the Eyring’s plastic flow model in which yielding is described.

  16. Low Molecular Weight Fucoidan Inhibits Tumor Angiogenesis through Downregulation of HIF-1/VEGF Signaling under Hypoxia

    Meng-Chuan Chen

    2015-07-01

    Full Text Available Activation of hypoxia-induced hypoxia-inducible factors-1 (HIF-1 plays a critical role in promoting tumor angiogenesis, growth and metastasis. Low molecular weight fucoidan (LMWF is prepared from brown algae, and exhibits anticancer activity. However, whether LMWF attenuates hypoxia-induced angiogenesis in bladder cancer cells and the molecular mechanisms involved remain unclear. This is the first study to demonstrate that LMWF can inhibit hypoxia-stimulated H2O2 formation, HIF-1 accumulation and transcriptional activity vascular endothelial growth factor (VEGF secretion, and the migration and invasion in hypoxic human bladder cancer cells (T24 cells. LMWF also downregulated hypoxia-activated phosphorylation of PI3K/AKT/mTOR/p70S6K/4EBP-1 signaling in T24 cells. Blocking PI3K/AKT or mTOR activity strongly diminished hypoxia-induced HIF-1α expression and VEGF secretion in T24 cells, supporting the involvement of PI3K/AKT/mTOR in the induction of HIF-1α and VEGF. Additionally, LMWF significantly attenuated angiogenesis in vitro and in vivo evidenced by reduction of tube formation of hypoxic human umbilical vascular endothelial cells and blood capillary generation in the tumor. Similarly, administration of LMWF also inhibited the HIF-1α and VEGF expression in vivo, accompanied by a reduction of tumor growth. In summary, under hypoxia conditions, the antiangiogenic activity of LMWF in bladder cancer may be associated with suppressing HIF-1/VEGF-regulated signaling pathway.

  17. Equilibrating high-molecular-weight symmetric and miscible polymer blends with hierarchical back-mapping

    Ohkuma, Takahiro; Kremer, Kurt; Daoulas, Kostas

    2018-05-01

    Understanding properties of polymer alloys with computer simulations frequently requires equilibration of samples comprised of microscopically described long molecules. We present the extension of an efficient hierarchical backmapping strategy, initially developed for homopolymer melts, to equilibrate high-molecular-weight binary blends. These mixtures present significant interest for practical applications and fundamental polymer physics. In our approach, the blend is coarse-grained into models representing polymers as chains of soft blobs. Each blob stands for a subchain with N b microscopic monomers. A hierarchy of blob-based models with different resolution is obtained by varying N b. First the model with the largest N b is used to obtain an equilibrated blend. This configuration is sequentially fine-grained, reinserting at each step the degrees of freedom of the next in the hierarchy blob-based model. Once the blob-based description is sufficiently detailed, the microscopic monomers are reinserted. The hard excluded volume is recovered through a push-off procedure and the sample is re-equilibrated with molecular dynamics (MD), requiring relaxation on the order of the entanglement time. For the initial method development we focus on miscible blends described on microscopic level through a generic bead-spring model, which reproduces hard excluded volume, strong covalent bonds, and realistic liquid density. The blended homopolymers are symmetric with respect to molecular architecture and liquid structure. To parameterize the blob-based models and validate equilibration of backmapped samples, we obtain reference data from independent hybrid simulations combining MD and identity exchange Monte Carlo moves, taking advantage of the symmetry of the blends. The potential of the backmapping strategy is demonstrated by equilibrating blend samples with different degree of miscibility, containing 500 chains with 1000 monomers each. Equilibration is verified by comparing

  18. Prematurity and low weight at birth as new conditions predisposing to an increased cardiovascular risk.

    Mercuro, Giuseppe; Bassareo, Pier Paolo; Flore, Giovanna; Fanos, Vassilios; Dentamaro, Ilaria; Scicchitano, Pietro; Laforgia, Nicola; Ciccone, Marco Matteo

    2013-04-01

    Although the survival rate for preterm subjects has improved considerably, due to the progress in the field of perinatal medicine, preterm birth is frequently the cause underlying a series of notorious complications: morphological, neurological, ophthalmological, and renal alterations. In addition, it has recently been demonstrated how low gestational age and reduced foetal growth contribute towards an increased cardiovascular risk in preterm neonates. In fact, cardiovascular mortality is higher among former preterm adults than those born at term. This condition is referred to as cardiovascular perinatal programming. In the light of the above, an early, constant, and prolonged cardiological followup programme should be implemented in former preterm individuals. The aim of this paper was to perform a comprehensive literature review about two new emerging conditions predisposing to an increased cardiovascular risk: prematurity and low weight at birth.

  19. Early pair housing increases solid feed intake and weight gains in dairy calves.

    Costa, J H C; Meagher, R K; von Keyserlingk, M A G; Weary, D M

    2015-09-01

    Dairy calves have traditionally been kept in individual pens throughout the milk-feeding period. Social rearing is associated with increased solid feed intake and, hence, higher weight gains before and after weaning. Little is known about the effect of the age at which social housing begins. The aim of this study was to assess the effects of early versus late pairing on feeding behavior and weight gain before and after weaning. Holstein bull calves were reared individually (n=8 calves) or paired with another calf at 6±3 d (n=8 pairs) or 43±3 d of age (n=8 pairs). All calves were fed 8 L of milk/d for 4 wk, 6 L/d from 4 to 7 wk, and then milk was reduced by 20%/d until calves were completely weaned at 8 wk of age. Calves were provided ad libitumaccess to calf starter and a total mixed ration (TMR). Body weight and feed intake were measured weekly from 3 to 10 wk of age.Intake of calf starter was significantly higher for the early-paired calves than for individually reared and late-paired calves throughout the experimental period. At 10 wk of age, starter dry matter intake averaged 2.20±0.22, 1.09±0.25, and 1.26±0.33kg/d for early-paired, late-paired, and individually housed calves, respectively. Intake of TMR did not differ among treatments, TMR dry matter intake averaged 3.27±0.72, 3.08±0.46, and 2.89±0.54kg/d for the same 3 treatments. Calves in the early paired treatment also showed significantly higher average daily gain over the experimental period (0.89±0.04 vs. 0.76±0.04 and 0.73±0.04kg/d for the early-paired, individual, and late-paired calves, respectively). These results indicate that social housing soon after birth can increase weight gains and intake of solid feed. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  20. Increased levels of circulating arginase I in overweight compared to normal weight adolescents.

    Jung, Christian; Figulla, Hans R; Lichtenauer, Michael; Franz, Marcus; Pernow, John

    2014-02-01

    Overweight and the metabolic syndrome have become major problems, especially in children and adolescents. Obesity at a young age increases the risk for cardiovascular diseases and diabetes mellitus later in life. An early event in the development of cardiovascular disease is endothelial dysfunction which is found in obese young individuals. Increased activity of the enzyme arginase has been described as a central mechanism for endothelial dysfunction, especially in patients with diabetes mellitus. The aim of the study was to determine plasma levels of arginase in overweight adolescents. Sixty-six male German adolescents (age: 15.2 ± 1.1 years old) were included. Thirty-one of them were overweight (>90th age-specific weight percentile). Plasma arginase I and tumor necrosis factor alpha (TNFα) were determined. In addition, clinical data were recorded and anthropometrical measurements of obesity were performed. Overweight adolescents had a higher systolic blood pressure, lower high-density lipoprotein and increased levels of high-sensitive C-reactive protein (CRP). Circulating arginase I was elevated in overweight adolescents (95.8 ± 68.2 ng/ml) compared to normal weight adolescents (39.3 ± 26.9 ng/ml, p obesity. There was no difference between the two groups regarding TNFα. We demonstrate that arginase I levels are increased in obese adolescents. Knowing the important role for arginase in endothelial dysfunction, elevated levels of arginase I may represent a link between obesity, endothelial dysfunction and related comorbidities. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. Meditations on birth weight: is it better to reduce the variance or increase the mean?

    Haig, David

    2003-07-01

    A conceptual model is presented here in which the birth weight distribution is decomposed into a distribution of target weights and a distribution of perturbations from the target. The target weight is the adaptive goal of fetal development. In the simplest model, perinatal mortality is independent of variation in target weight and determined solely by the magnitude of the perturbation of birth weight from the target. In this model, mortality risk is concentrated in the tails of the birth weight distribution. A difference between populations in their distributions of target weights will be associated with a corresponding shift in their curves of weight-specific risk, without any difference between the populations in overall risk. In this model, risk would be reduced by decreasing the variance of the distribution of perturbations. The model is discussed in the context of the so-called "paradoxes of low birth weight."

  2. Ultra-Fast RAFT-HDA Click Conjugation: An Efficient Route to High Molecular Weight Block Copolymers.

    Inglis, Andrew J; Stenzel, Martina H; Barner-Kowollik, Christopher

    2009-11-02

    The use of the reversible addition fragmentation chain transfer-hetero Diels-Alder (RAFT-HDA) click reaction for the modular construction of block copolymers is extended to the generation of high molecular weight materials. Cyclopentadienyl end-functionalized polystyrene (PS-Cp) prepared via both atom transfer radical polymerization (ATRP) and the RAFT process are conjugated to poly(isobornyl acrylate) (PiBoA) (also prepared via RAFT polymerization) to achieve well-defined block copolymers with molecular weights ranging from 34 000 to over 100 000 g · mol(-1) and with small polydispersities (PDI HDA click chemistry can provide access to high molecular weight block copolymers in a simple and straight-forward fashion. Copyright © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Trapping dynamics of isobutane, n-butane, and neopentane on Pt(111): Effects of molecular weight and structure

    Weaver, J.F.; Madix, R.J.

    1999-01-01

    The molecular adsorption dynamics of isobutane, n-butane, and neopentane on Pt(111) was investigated using supersonic molecular beam techniques and stochastic trajectory calculations. Using the united atom approach, a single, pairwise-additive Morse Potential for methyl (methylene)- plantinum interactions quantitatively simulates the dependence of the initial trapping probability, α, on the initial translational energy, E T , and angle of incidence, θ i , for each alkane. For both isobutane and n-butane, the dependence of α on E T and θ i best scales with E T cos 0.8 θ i , which is similar to that found previously for ethane and propane trapping on Pt(111). The initial trapping probability of neopentane exhibits a more pronounced dependence on θ i , which scales according to E T cos 1.3 θ i . The simulations suggest that the enhanced angular dependence of α for neopentane is related to its molecular weight. As the mass of the incident species is increased, momentum transfer to the surface becomes more efficient than the interconversion of incident parallel and normal momentum due to corrugation of the surface potential. The net effect is an increase in the trapping probability at glancing incidence compared to lighter molecules, and a resulting shift in the angular dependence of α towards normal energy scaling. The calculations also predict that collisional energy transfer to rotation is important in promoting adsorption. For each molecule, rotational excitation is determined to be the most effective energy transfer process that discriminates trapping from scattering. In addition, translational energy transfer to torsional vibration about the central C - C bond is highly efficient for n-butane, and greatly facilitates adsorption. Less excitation is predicted for C - C - C bending modes for all of these molecules. copyright 1999 American Institute of Physics

  4. Tributyltin exposure induces gut microbiome dysbiosis with increased body weight gain and dyslipidemia in mice.

    Guo, Hao; Yan, Haotian; Cheng, Dong; Wei, Xinglong; Kou, Ruirui; Si, Jiliang

    2018-05-03

    Gut microbiome dysbiosis plays a profound role in the pathogenesis of obesity and tributyltin (TBT) has been found as an environmental obesogen. However, whether TBT could disturb gut microbiome and the relationship between obesity induced by TBT exposure and alteration in gut microbiota are still unknown. In order to assess the association between them, mice were exposed to TBTCl (50 μg kg -1 ) once every three days from postnatal days (PNDs) 24 to 54. The results demonstrated that TBT exposure resulted in increased body weight gain, lager visceral fat accumulation and dyslipidemia in male mice on PND 84. Correspondingly, 16S rRNA gene sequencing revealed that TBT treatment decreased gut microbial species and perturbed the microbiome composition in mice. Furthermore, Pearson's corelation coefficient analysis showed a significantly negative correlation between the body weight and the alpha diversity of gut microbiome. These results suggested that TBT exposure could induce gut microbiome dysbiosis in mice, which might contribute to the obesity pathogenesis. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. [Influence of low birth weight on the increased risk of post-partum hypertension].

    Wang, Lijiao; Tian, Qi; Wu, Aiping; Kan, Shuting; Tao, Jie; Dong, Yan; Han, Hongfeng; Gao, Xinying; Zheng, Yao; Chen, Shuohua; Wu, Shouling

    2014-07-01

    To compare the prevalence of hypertension between low birth weight infant (LBWI) women and non-LBWI women. A retrospective cohort study was applied and 3 172 pregnant women giving births during October 1976 to December 2008 in our hospital and underwent physical check-up between 2010 and 2011 at the Kailuan medical group were included and divided into LBWI group and non-LBWI group by the history of LBWI. Prevalence of hypertension was obtained during the follow-up program. Multiple logistic regression analysis was used to assess the relative risk of hypertension. A total number of 3 172 women, with an average age of 42.3 years old were divided into LBWI group (n = 147) and non-LBWI group (n = 3 025), with the average birth weights of their infants were 2.31 kg and 3.39 kg, respectively. The prevalence of hypertension from the follow-up program was significantly higher in LBWI group than that in the non-LBWI group (23.8% vs. 16.9%, P hypertension in LBWI group was 1.60 (95%CI:1.02-2.53) folds higher than that in the non-LBWI group. Prevalence of hypertension in women with LBWI was higher than that in those women without LBWI. History of LBWI seemed to have had an increased risk to develop hypertension.

  6. Microbial utilization of low molecular weight organic substrates in soil depends on their carbon oxidation state

    Gunina, Anna; Smith, Andrew; Jones, Davey; Kuzyakov, Yakov

    2017-04-01

    Removal of low molecular weight organic substances (LMWOS), originating from plants and microorganisms, from soil solution is regulated by microbial uptake. In addition to the concentration of LMWOS in soil solution, the chemical properties of each substance (e.g. C oxidation state, number of C atoms, number of -COOH groups) can affect their uptake and subsequent partitioning of C within the soil microbial community. The aim of this study was to trace the initial fate of three dominant classes of LMWOS in soil (sugars, carboxylic and amino acids), including their removal from solution and utilization by microorganisms, and to reveal the effect of substance chemical properties on these processes. Soil solution, spiked at natural abundance levels with 14C-labelled glucose, fructose, malate, succinate, formate, alanine or glycine, was added to the soil and 14C was traced in the dissolved organic carbon (DOC), CO2, cytosol and soil organic carbon (SOC) over 24 hours. The half-life time of all LMWOS in the DOC (T1 /2-solution) varied between 0.6-5.0 min showing extremely fast initial uptake of LMWOS. The T1 /2-solution of substances was dependent on C oxidation state, indicating that less oxidized organic substances (with C oxidation state "0") were retained longer in soil solution than oxidized substances. The LMWOS-C T1 /2-fast, characterizing the half-life time of 14C in the fast mineralization pool, ranged between 30 and 80 min, with the T1 /2-fast of carboxylic acids (malic acid) being the fastest and the T1 /2-fast of amino acids (glycine) being the slowest. An absence of correlation between T1 /2-fast and either C oxidation state, number of C atoms, or number of -COOH groups suggests that intercellular metabolic pathways are more important for LMWOS transformation in soil than their basic chemical properties. The CO2 release during LMWOS mineralization accounted for 20-90% of 14C applied. Mineralization of LMWOS was the least for sugars and the greatest for

  7. Separation of both fibrous and globular proteins on the basis of molecular weight using high-performance size exclusion chromatography.

    Barden, J A

    1983-11-01

    A high-performance size exclusion liquid chromatographic system has been used to separate proteins with different shapes solely on the basis of their molecular weights. After the effects of ionic and hydrophobic interactions with the stationary phase have been overcome, protein elution is normally governed by their effective size in solution. Conditions are described under which proteins, with isoelectric points within the normal operating pH range of the columns, are eluted independent of their Stokes' radii. Even fibrous proteins with axial ratios of 50 elute according to their known molecular weights over the range 2000-2,000,000.

  8. Preparation of Low Allergenic Protein Concentrated Natural Rubber Latex Using Suitable Low Molecular Weight Cellulose Derivatives Induced by Gamma Irradiation

    Siri-Upathum, Chyagrit; Boonyawat, Jariya

    2007-08-01

    Full text: Low molecular weight carboxy methyl cellulose (CMC), hydroxyl ethyl cellulose (HEC), hydroxyl propyl cellulose (HPC) and methyl cellulose (MC) prepared by radiation-induced degradation were added into diluted natural concentrated latex prior to centrifuge for a purpose of reducing allergenic rubber protein in the latex. Optimum molecular weight (Mv) of CMC and HEC for such a purpose was found to be 17-18 kDa which decreased allergenic rubber protein (14-94 kDa) to an undetectable amount as determined by SDS PAGE method

  9. Conductivity, dielectric behavior and FTIR studies of high molecular weight poly(vinylchloride)-lithium triflate polymer electrolytes

    Ramesh, S.; Chai, M.F.

    2007-01-01

    Thin films of high molecular weight polyvinyl chloride (PVC) with lithium triflate (LiCF 3 SO 3 ) salt were prepared by solution casting method. The ionic conductivity and dielectric measurements were carried out on these films over a wide frequency regime at various temperatures. The conductivity-temperature plots were found to obey classical Arrhenius relationship. The dielectric behavior was analysed using dielectric permittivity and dielectric modulus of the samples. FTIR studies show some simple overlapping and shift in peaks between high molecular weight polyvinyl chloride (PVC) with lithium triflate (LiCF 3 SO 3 ) salt in the polymer electrolyte complexes

  10. Conductivity, dielectric behavior and FTIR studies of high molecular weight poly(vinylchloride)-lithium triflate polymer electrolytes

    Ramesh, S. [Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Setapak, 53300 Kuala Lumpur (Malaysia)]. E-mail: ramesh@mail.utar.edu.my; Chai, M.F. [Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Setapak, 53300 Kuala Lumpur (Malaysia)

    2007-05-15

    Thin films of high molecular weight polyvinyl chloride (PVC) with lithium triflate (LiCF{sub 3}SO{sub 3}) salt were prepared by solution casting method. The ionic conductivity and dielectric measurements were carried out on these films over a wide frequency regime at various temperatures. The conductivity-temperature plots were found to obey classical Arrhenius relationship. The dielectric behavior was analysed using dielectric permittivity and dielectric modulus of the samples. FTIR studies show some simple overlapping and shift in peaks between high molecular weight polyvinyl chloride (PVC) with lithium triflate (LiCF{sub 3}SO{sub 3}) salt in the polymer electrolyte complexes.

  11. Increasing Low Birth Weight Rates: Deliveries in a Tertiary Hospital in Istanbul

    Berrin Telatar; Orhan Ünal; Abdülkadir Piçak; Lale Ger; Serdar Cömert; Cem Turan; Yasemin Akin

    2010-01-01

    Objective:Prevalence of low birth weight deliveries may vary across different environments. The necessity of determination of regional data prompted this study. Methods:Information of all deliveries from January 2004 to December 2008 was obtained from delivery registry records retrospectively. Initial data including birth weight, vital status, sex, maternal age and mode of delivery were recorded using medical files. The frequency of low birth weight, very low birth weight, extremely low birth...

  12. The Use of Radiation-Induced Degradation in Controlling Molecular Weights of Polysaccharides : The Effect of Humidity

    Sen, M.

    2006-01-01

    Better understanding of chemistry of radiation-induced degradation is becoming of increasing importance on account of the utilization of polymeric materials in a variety of radiation environments as well as beneficial uses of degraded polymers. It is very well known that polysaccharides in dry form or in solution degrade when exposed to ionizing radiation. In this study degrading effect of radiation has been considered from the point of view of controlling the molecular weights of kappa- and iota-carrageenans and sodium alginate irradiated under varying environmental conditions. The humidity equilibrated polymer samples kept over saturated aqueous salt solutions of NaCl, NaNO 3 and MgCl 2 were irradiated in a Gammacell 220 at room temperature. The degradation was investigated in detail by a careful Gel Permeation Chromatographic analysis of their respective molecular weights before and after irradiation Alexander-Charlesby-Ross equation was used in determining their radiation-chemical yields. Degradation yield is the highest for dry irradiated kappa- (G(S) = 0.73) and iota-carrageenans (G(S) = 2.43) and with small amount of water taken up from surrounding humidity degradation becomes less pronounced and G(S) values show a decrease down to G(S) = 0.16 and 0.87 at 75 % relative humidity, respectively. At very high water contents degradation effect again becomes more effective. Sodium alginate has fount to be less sensitive to the effect of humidity. When there is small amount of water in the polysaccharide structure, it is unlikely to expect an indirect effect of radiation. The water located in between the polymer chains however can give enough mobility to kappa and iota karrageenans chains, plastifying effect, which may enhance the radical-radical combinations thus lowering the rate of degradation hence reducing G(S) values

  13. Poly(mono/diethylene glycol n-tetradecyl ether vinyl ethers with Various Molecular Weights as Phase Change Materials

    Dongfang Pei

    2018-02-01

    Full Text Available At present, research on the relationship of comb-like polymer phase change material structures and their heat storage performance is scarce. Therefore, this relationship from both micro and macro perspectives will be studied in this paper. In order to achieve a high phase change enthalpy, ethylene glycol segments were introduced between the vinyl and the alkyl side chains. A series of poly(mono/diethylene glycol n-tetradecyl ether vinyl ethers (PC14EnVEs (n = 1, 2 with various molecular weights were polymerized by living cationic polymerization. The results of PC14E1VE and PC14E2VE showed that the minimum number of carbon atoms required for side-chain crystallization were 7.7 and 7.2, which were lower than that reported in the literature. The phase change enthalpy 89 J/g (for poly(mono ethylene glycol n-tetradecyl ether vinyl ethers and 86 J/g (for poly(hexadecyl acrylate were approximately equal. With the increase of molecular weight, the melting temperature, the melting enthalpy, and the initial thermal decomposition temperature of PC14E1VE changed from 27.0 to 28.0 °C, from 95 to 89 J/g, and from 264 to 287 °C, respectively. When the number average molar mass of PC14EnVEs exceeded 20,000, the enthalpy values remained basically unchanged. The introduction of the ethylene glycol chain was conducive to the crystallization of alkyl side chains.

  14. Increasing illness severity in very low birth weight infants over a 9-year period

    Locke Robert G

    2006-02-01

    Full Text Available Abstract Background Recent reports have documented a leveling-off of survival rates in preterm infants through the 1990's. The objective of this study was to determine temporal changes in illness severity in very low birth weight (VLBW infants in relationship to the outcomes of death and/or severe IVH. Methods Cohort study of 1414 VLBW infants cared for in a single level III neonatal intensive care unit in Delaware from 1993–2002. Infants were divided into consecutive 3-year cohorts. Illness severity was measured by two objective methods: the Score for Neonatal Acute Physiology (SNAP, based on data from the 1st day of life, and total thyroxine (T4, measured on the 5th day of life. Death before hospital discharge and severe intraventricular hemorrhage (IVH were investigated in the study sample in relation to illness severity. The fetal death rate was also investigated. Statistical analyses included both univariate and multivariate analysis. Results Illness severity, as measured by SNAP and T4, increased steadily over the 9-year study period with an associated increase in severe IVH and the combined outcome of death and/or severe IVH. During the final 3 years of the study, the observed increase in illness severity accounted for 86% (95% CI 57–116% of the variability in the increase in death and/or severe IVH. The fetal death rate dropped from 7.8/1000 (1993–1996 to 5.3/1000 (1999–2002, p = .01 over the course of the study. Conclusion These data demonstrate a progressive increase in illness in VLBW infants over time, associated with an increase in death and/or severe IVH. We speculate that the observed decrease in fetal death, and the increase in neonatal illness, mortality and/or severe IVH over time represent a shift of severely compromised patients that now survive the fetal time period and are presented for care in the neonatal unit.

  15. Molecular biomarkers for weight control in obese individuals subjected to a multi-phase dietary intervention

    Bolton, Jennifer L; Montastier, Emilie; Carayol, Jérôme

    2017-01-01

    Context: While calorie restriction has proven beneficial for weight loss, long-term weight control is variable between individuals. Objective: To identify biomarkers of successful weight control during a dietary intervention (DI). Design, Setting, and Participants: Adipose tissue (AT) transcripto......-controllers. Interestingly, ASPN is a TGFβ1 inhibitor. Conclusions: We found circulating biomarkers associated with weight control, which could influence weight management strategies, and genes that may be prognostic for successful weight control....

  16. The prevalence of Type 2 diabetes is not increased in normal-weight women with PCOS

    Pelanis, Rasa; Mellembakken, Jan Roar; Sundström-Poromaa, Inger

    2017-01-01

    of prediabetes and Type 2 diabetes (T2D) which is closely linked to obesity and possibly age, ethnicity and PCOS phenotype. Several guidelines recommend OGTT upon diagnosis of PCOS and during follow-up. STUDY DESIGN, SIZE, DURATION: A Nordic cross-sectional study including 876 women. PARTICIPANTS....../MATERIALS, SETTING, METHODS: The 876 Nordic women with PCOS, aged 14-57 years, were examined for T2D and prediabetes (impaired glucose tolerance [IGT] or impaired fasting glucose (IFG) by OGTT. MAIN RESULT AND THE ROLE OF CHANCE: Of all study subjects 3% (23/876) had T2D, 23% (204/876) prediabetes and 74% (649....../876) had normal glucose tolerance (NGT). Increased BMI and waist circumference were significantly (P prediabetes and T2D. No normal-weight woman (BMI

  17. Low molecular weight components in an aquatic humic substance as characterized by membrane dialysis and orbitrap mass spectrometry.

    Remucal, Christina K; Cory, Rose M; Sander, Michael; McNeill, Kristopher

    2012-09-04

    Suwannee River fulvic acid (SRFA) was dialyzed through a 100-500 molecular weight cutoff dialysis membrane, and the dialysate and retentate were analyzed by UV-visible absorption and high-resolution Orbitrap mass spectrometry (MS). A significant fraction (36% based on dissolved organic carbon) of SRFA passed through the dialysis membrane. The fraction of SRFA in the dialysate had a different UV-visible absorption spectrum and was enriched in low molecular weight molecules with a more aliphatic composition relative to the initial SRFA solution. Comparison of the SRFA spectra collected by Orbitrap MS and Fourier transform ion cyclotron resonance MS (FT-ICR MS) demonstrated that the mass accuracy of the Orbitrap MS is sufficient for determination of unique molecular formulas of compounds with masses masses detected by Orbitrap MS were found in the 100-200 Da mass range. Many of these low molecular masses corresponded to molecular formulas of previously identified compounds in organic matter, lignin, and plants, and the use of the standard addition method provided an upper concentration estimate of selected target compounds in SRFA. Collectively, these results provide evidence that SRFA contains low molecular weight components that are present individually or in loosely bound assemblies.

  18. Low molecular weight heparin for prevention of venous thromboembolism in patients with lower-leg immobilization.

    Testroote, Mark; Stigter, Willem A H; Janssen, Loes; Janzing, Heinrich M J

    2014-04-25

    Immobilization of the lower leg is associated with venous thromboembolism (VTE). Low molecular weight heparin (LMWH) is an anticoagulant treatment which might be used in adult patients with lower-leg immobilization to prevent deep venous thrombosis (DVT) and its complications. This is an update of the review first published in 2008. To assess the effectiveness of low molecular weight heparin for the prevention of venous thromboembolism in patients with lower-leg immobilization in an ambulant setting. For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched June 2013) and CENTRAL (2013, Issue 5). Randomized controlled trials (RCTs) and controlled clinical trials (CCTs) that described thromboprophylaxis by means of LMWH compared with no prophylaxis or placebo in adult patients with lower-leg immobilization. Immobilization was by means of a plaster cast or brace. Two authors independently assessed trial quality and extracted data. The review authors contacted the trial authors for additional information if required. Statistical analysis was carried out using Review Manager (RevMan 5). We included six RCTs fulfilling the above criteria with a total of 1490 patients. We found an incidence of VTE ranging from 4.3% to 40% in patients who had a leg injury that had been immobilized in a plaster cast or a brace for at least one week and who received no prophylaxis, or placebo. This number was significantly lower in patients who received daily subcutaneous injections of LMWH during immobilization (event rates ranging from 0% to 37%; odds ratio (OR) 0.49; fixed 95% confidence interval (CI) 0.34 to 0.72; with minimal evidence of heterogeneity with an I(2) of 20%, P = 0. 29). Comparable results were seen in the following subcategories: operated patients, conservatively treated patients, patients with fractures, patients with soft-tissue injuries, patients with proximal thrombosis, patients with

  19. Cardiac natriuretic peptides in plasma increase after dietary induced weight loss in obesity.

    Kistorp, Caroline; Bliddal, Henning; Goetze, Jens P; Christensen, Robin; Faber, Jens

    2014-01-01

    Cardiac natriuretic peptides are established biomarkers in heart disease, but are also affected by body mass index (BMI). The purpose of the present study was to examine the impact of weight loss and changes in body composition following dietary intervention on plasma concentrations of the prohormones to A- and B-type natriuretic peptides (proANP and proBNP) and adrenomedullin (proADM). A total of 52 healthy obese subjects, 47 women and 5 men (BMI 36.5 ± 5.6 kg/m(2)) were randomised to either an intensive weight reduction programme using a combination of very low calorie diet (810 kcal/day) and conventional hypo-energetic diet (1200 kcal/day) for 52 weeks, or to a control group that was offered diet-related counselling. N-terminal proBNP (NT-proBNP), mid-regional proANP (MR-proANP) and proADM (MR-proADM) and body composition using dual-energy x-ray absorptiometry (DEXA) scanning were determined at baseline and after 52 weeks. Comparisons between groups were analysed using t-tests. Changes from the baseline within the groups were analysed with paired tests. Changes in the variables, delta (∆), were calculated as 52 weeks minus the baseline. In the intervention group, BMI decreased by almost 20% (31.6 ± 6.2 vs. 37.1 ± 6.1 kg/m(2); P <0.001) with a loss of body fat of 23.5 ± 15.5% (P < 0.001). Plasma concentrations of NT-proBNP and MR-proANP increased (from 55 ± 31 to 97 ± 55 pg/ml; P < 0.001, and from 59 ± 21 to 74 ± 26 pmol/L; P < 0.001), whereas MR-proADM decreased (from 573 ± 153 to 534 ± 173 pmol/L; P <0.001). Changes (Δ) in MR-proANP correlated with Δfat mass (r = -0.359; P = 0.011) and Δglucose (r = -0.495; P <0.001), while increases in NT-proBNP were primarily associated with reduced plasma glucose (r = -0.462; P <0.001). A modest but significant weight loss of 6% (P < 0.001) was found in the control group with no changes in plasma concentrations of NT-proBNP or MR-proANP, and a minor change in MR-proADM. Plasma NT-proBNP and MR

  20. Increase in Fracture Risk Following Unintentional Weight Loss in Postmenopausal Women: The Global Longitudinal Study of Osteoporosis in Women†

    Compston, Juliet E.; Wyman, A; FitzGerald, Gordon; Adachi, Jonathan D.; Chapurlat, Roland D.; Cooper, Cyrus; Díez-Pérez, Adolfo; Gehlbach, Stephen H; Greenspan, Susan L.; Hooven, Frederick H.; LaCroix, Andrea Z.; March, Lyn; Coen Netelenbos, J.; Nieves, Jeri W.; Pfeilschifter, Johannes; Rossini, Maurizio; Roux, Christian; Saag, Kenneth G.; Siris, Ethel S.; Silverman, Stuart; Watts, Nelson B.; Anderson, Frederick A.

    2016-01-01

    Increased fracture risk has been associated with weight loss in postmenopausal women but the time course over which this occurs has not been established. The aim of this study was to examine the effects of unintentional weight loss of ≥10 lb (4.5 kg) in postmenopausal women on fracture risk at multiple sites up to 5 years following weight loss. Using data from the Global Longitudinal Study of Osteoporosis in Women (GLOW) we analyzed the relationships between self-reported unintentional weight loss of ≥10 lb at baseline, year 2, or year 3 and incident clinical fracture in the years following weight loss. Complete data were available in 40,179 women (mean age ± SD 68 ± 8.3 years). Five-year cumulative fracture rate was estimated using the Kaplan-Meier method, and adjusted hazard ratios for weight loss as a time-varying covariate were calculated from Cox multiple regression models. Unintentional weight loss at baseline was associated with a significantly increased risk of fracture of the clavicle, wrist, spine, rib, hip, and pelvis for up to 5 years following weight loss. Adjusted hazard ratios showed a significant association between unintentional weight loss and fracture of the hip, spine, and clavicle within 1 year of weight loss, and these associations were still present at 5 years. These findings demonstrate increased fracture risk at several sites after unintentional weight loss in postmenopausal women. This increase is seen as early as 1 year following weight loss, emphasizing the need for prompt fracture risk assessment and appropriate management to reduce fracture risk in this population. PMID:26861139

  1. Excess body weight in children may increase the length of hospital stay

    Maria Teresa Bechere Fernandes

    2015-02-01

    Full Text Available OBJECTIVES: To investigate the prevalence of excess body weight in the pediatric ward of University Hospital and to test both the association between initial nutritional diagnosis and the length of stay and the in-hospital variation in nutritional status. METHODS: Retrospective cohort study based on information entered in clinical records from University Hospital. The data were collected from a convenience sample of 91 cases among children aged one to 10 years admitted to the hospital in 2009. The data that characterize the sample are presented in a descriptive manner. Additionally, we performed a multivariate linear regression analysis adjusted for age and gender. RESULTS: Nutritional classification at baseline showed that 87.8% of the children had a normal weight and that 8.9% had excess weight. The linear regression models showed that the average weight loss z-score of the children with excess weight compared with the group with normal weight was −0.48 (p = 0.018 and that their length of stay was 2.37 days longer on average compared with that of the normal-weight group (p = 0.047. CONCLUSIONS: The length of stay and loss of weight at the hospital may be greater among children with excess weight than among children with normal weight.

  2. Preparation of High Modulus Poly(Ethylene Terephthalate: Influence of Molecular Weight, Extrusion, and Drawing Parameters

    Jian Min Zhang

    2017-01-01

    Full Text Available Poly(ethylene terephthalate (PET which is one of the most commercially important polymers, has for many years been an interesting candidate for the production of high performance fibres and tapes. In current study, we focus on investigating the effects of the various processing variables on the mechanical properties of PET produced by a distinctive process of melt spinning and uniaxial two-stage solid-state drawing (SSD. These processing variables include screw rotation speed during extrusion, fibre take-up speed, molecular weight, draw-ratio, and drawing temperature. As-spun PET production using a single-screw extrusion process was first optimized to induce an optimal polymer microstructure for subsequent drawing processes. It was found that less crystallization which occurred during this process would lead to better drawability, higher draw-ratio, and mechanical properties in the subsequent SSD process. Then the effect of drawing temperature (DT in uniaxial two-stage SSD process was studied to understand how DT (

  3. Effect of molecular weight, temperature, and additives on the moisture sorption properties of polyethylene glycol.

    Baird, Jared A; Olayo-Valles, Roberto; Rinaldi, Carlos; Taylor, Lynne S

    2010-01-01

    Polyethylene glycol (PEG) is a hygroscopic polymer that undergoes the phenomenon of deliquescence once a critical relative humidity (RH(0)) is reached. The purpose of this study was to test the hypothesis that the deliquescence behavior of PEG will be affected by the polymer molecular weight, temperature, and the presence of additives. The deliquescence relative humidity for single component (RH(0)) and binary mixtures (RH(0,mix)) were measured using an automated gravimetric moisture analyzer at 25 and 40 degrees C. Changes in PEG crystallinity after exposure to moisture were qualitatively assessed using powder X-ray diffraction (PXRD). Optical microscopy was used to visually observe the deliquescence phenomenon. For single component systems, decreasing PEG MW and elevating the temperature resulted in a decrease in the observed RH(0). Physical mixtures of acetaminophen and anhydrous citric acid with both PEG 3350 and PEG 100,000 exhibited deliquescence (RH(0,mix)) at a relative humidity below that of either individual component. Qualitative changes in crystallinity were observed from the X-ray diffractograms for each PEG MW grade at high relative humidities, indicating that phase transformation (deliquescence) of the samples had occurred. In conclusion, it was found that the deliquescence behavior of PEG was affected by the polymer MW, temperature, and the presence of additives. This phenomenon may have important implications for the stability of PEG containing formulations.

  4. Partial characterization of a low molecular weight human collagen that undergoes alternative splicing

    Pihlajaniemi, T.; Myllylea, R.; Kurkinen, M.; Prockop, D.J.

    1987-01-01

    A cDNA library prepared from RNA isolated from a cultured human tumor cell line, HT-1080, was screened with a mouse cDNA clone coding for part of the -Gly-Xaa-Yaa-domain of the α2(IV) collagen chain. Four overlapping cDNA clones were characterized that coded for a low molecular weight human collagen. The cDNA clones did not, however, code for the short-chain collagens, types IX and X. The amino acid sequences derived from the clones resembled type IV collagen in that there were short interruptions in the repeating -Gly-Xaa-Yaa-sequence. The noncollagenous, carboxyl-terminal domain was, however, much shorter and contained only 18 amino acid residues. Interestingly, one of the cDNA clones contained an additional 36 nucleotides not found in an overlapping clone. The 36 nucleotides encoded four -Gly-Xaa-Yaa-repeats without changing the reading frame. Nuclease S1 mapping using a 32 P-labelled probe demonstrated that the different between the clones was due to existence of two different mRNAs. A synthetic 24-residue peptide corresponding to the last two -Gly-Xaa-Yaa-triplets and the entire carboxyl-terminal domain was used to generate polyclonal antibodies. Electrophoretic transfer blot analysis of HT-1080 cells and normal human skin fibroblasts identified two polypeptides, M/sub r/ 67,000 and M/sub r/ 62,000, that were sensitive to bacterial collagenase

  5. Macroradical reaction in ultra-high molecular weight polyethylene in the presence of vitamin E

    Jahan, M.S.; Walters, B.M.

    2011-01-01

    Free radical measurements in compression molded ultra-high molecular weight polyethylene (UHMWPE), which contained vitamin E (α-tocopherol (α-T)), was performed using electron spin resonance (ESR) technique in air at room temperature following gamma irradiation (25-32 kGy) in N 2 . The vitamin E was incorporated into one set of samples by blending UHMWPE resin with vitamin E (1 and 10 wt%), then compression molded into a solid and then irradiated. Another set of samples had vitamin E incorporated into them by diffusing vitamin E at 100 o C for 2 h after irradiation. Compared to a control (with no vitamin E), the vitamin E-containing UHMWPE (α-TPE) samples suffered a partial loss of PE radicals, but this loss only occurred during or immediately after irradiation (before exposure to air). Subsequently, when all blended samples were exposed to air, the remaining radicals in each sample decayed to the well-known OIR, R1 (- · CH-[CH=CH-] m -) and R2 ( · OCH-[CH=CH-] m -) radicals. However, because of the initial loss or partial quenching, α-TPE produced a lower concentration of OIR (measured over a four-year period), but no difference was found between 1% and 10% α-TPEs. In the diffused α-TPE, similar OIR was also found when tested after four months of post-treatment exposure to air.

  6. Macroradical reaction in ultra-high molecular weight polyethylene in the presence of vitamin E

    Jahan, M.S., E-mail: mjahan@memphis.ed [Department of Physics, Biomaterials Research Laboratory, University of Memphis, 216 Manning Hall, Memphis, TN 38152 (United States); Walters, B.M. [Department of Physics, Biomaterials Research Laboratory, University of Memphis, 216 Manning Hall, Memphis, TN 38152 (United States)

    2011-02-15

    Free radical measurements in compression molded ultra-high molecular weight polyethylene (UHMWPE), which contained vitamin E ({alpha}-tocopherol ({alpha}-T)), was performed using electron spin resonance (ESR) technique in air at room temperature following gamma irradiation (25-32 kGy) in N{sub 2}. The vitamin E was incorporated into one set of samples by blending UHMWPE resin with vitamin E (1 and 10 wt%), then compression molded into a solid and then irradiated. Another set of samples had vitamin E incorporated into them by diffusing vitamin E at 100 {sup o}C for 2 h after irradiation. Compared to a control (with no vitamin E), the vitamin E-containing UHMWPE ({alpha}-TPE) samples suffered a partial loss of PE radicals, but this loss only occurred during or immediately after irradiation (before exposure to air). Subsequently, when all blended samples were exposed to air, the remaining radicals in each sample decayed to the well-known OIR, R1 (-{sup {center_dot}C}H-[CH=CH-]{sub m}-) and R2 ({sup {center_dot}O}CH-[CH=CH-]{sub m}-) radicals. However, because of the initial loss or partial quenching, {alpha}-TPE produced a lower concentration of OIR (measured over a four-year period), but no difference was found between 1% and 10% {alpha}-TPEs. In the diffused {alpha}-TPE, similar OIR was also found when tested after four months of post-treatment exposure to air.

  7. Circular dichroism studies of low molecular weight hydrogelators: The use of SRCD and addressing practical issues.

    Sitsanidis, Efstratios D; Piras, Carmen C; Alexander, Bruce D; Siligardi, Giuliano; Jávorfi, Tamás; Hall, Andrew J; Edwards, Alison A

    2018-04-12

    Circular dichroism (CD) spectroscopy has been used extensively for the investigation of the conformation and configuration of chiral molecules, but its use for evaluating the mode of self-assembly in soft materials has been limited. Herein, we report a protocol for the study of such materials by electronic CD spectroscopy using commercial/benchtop instruments and synchrotron radiation (SR) using the B23 beamline available at Diamond Light Source. The use of the B23 beamtime for SRCD was advantageous because of the unique enhanced spatial resolution achieved because of its highly collimated and small beamlight cross section (ca. 250 μm) and higher photon flux in the far UV region (175-250 nm) enhancing the signal-to-noise ratio relative to benchtop CD instruments. A set of low molecular weight (LMW) hydrogelators, comprising two Fmoc-protected enantiomeric monosaccharides and one Fmoc dipeptide (Fmoc-FF), were studied. The research focused on the optimization of sample preparation and handling, which then enabled the characterization of sample conformational homogeneity and thermal stability. CD spectroscopy, in combination with other spectroscopic techniques and microscopy, will allow a better insight into the self-assembly of chiral building blocks into higher order structural architectures. © 2018 Wiley Periodicals, Inc.

  8. Characterization and quantitation of low and high molecular weight phenolic compounds in apple seeds.

    Fromm, Matthias; Bayha, Sandra; Carle, Reinhold; Kammerer, Dietmar R

    2012-02-08

    The phenolic constituents of seeds of 12 different apple cultivars were fractionated by sequential extraction with aqueous acetone (30:70, v/v) and ethyl acetate after hexane extraction of the lipids. Low molecular weight phenolic compounds were individually quantitated by RP-HPLC-DAD. The contents of extractable and nonextractable procyanidins were determined by applying RP-HPLC following thiolysis and n-butanol/HCl hydrolysis, respectively. As expected, the results revealed marked differences of the ethyl acetate extracts, aqueous acetone extracts, and insoluble residues with regard to contents and mean degrees of polymerization of procyanidins. Total phenolic contents in the defatted apple seed residues ranged between 18.4 and 99.8 mg/g. Phloridzin was the most abundant phenolic compound, representing 79-92% of monomeric polyphenols. Yields of phenolic compounds significantly differed among the cultivars under study, with seeds of cider apples generally being richer in phloridzin and catechins than seeds of dessert apple cultivars. This is the first study presenting comprehensive data on the contents of phenolic compounds in apple seeds comprising extractable and nonextractable procyanidins. Furthermore, the present work points out a strategy for the sustainable and complete exploitation of apple seeds as valuable agro-industrial byproducts, in particular as a rich source of phloridzin and antioxidant flavanols.

  9. Laser surface modification of ultra-high-molecular-weight polyethylene (UHMWPE) for biomedical applications

    Riveiro, A.; Soto, R.; Val, J. del; Comesaña, R.; Boutinguiza, M.; Quintero, F.; Lusquiños, F.; Pou, J.

    2014-01-01

    Ultra-high-molecular-weight polyethylene (UHMWPE) is a synthetic polymer used for biomedical applications because of its high impact resistance, ductility and stability in contact with physiological fluids. Therefore, this material is being used in human orthopedic implants such as total hip or knee replacements. Surface modification of this material relates to changes on its chemistry, microstructure, roughness, and topography, all influencing its biological response. Surface treatment of UHMWPE is very difficult due to its high melt viscosity. This work presents a systematic approach to discern the role of different laser wavelengths (λ = 1064, 532, and 355 nm) on the surface modification of carbon coated UHMWPE samples. Influence of laser processing conditions (irradiance, pulse frequency, scanning speed, and spot overlapping) on the surface properties of this material was determined using an advanced statistical planning of experiments. A full factorial design of experiments was used to find the main effects of the processing parameters. The obtained results indicate the way to maximize surface properties which largely influence cell–material interaction.

  10. Surface functionalization of solid state ultra-high molecular weight polyethylene through chemical grafting

    Sherazi, Tauqir A.; Rehman, Tayyiba; Naqvi, Syed Ali Raza; Shaikh, Ahson Jabbar; Shahzad, Sohail Anjum; Abbas, Ghazanfar; Raza, Rizwan; Waseem, Amir

    2015-12-01

    The surface of ultra-high molecular weight polyethylene (UHMWPE) powder was functionalized with styrene using chemical grafting technique. The grafting process was initiated through radical generation on base polymer matrix in the solid state by sodium thiosulfate, while peroxides formed at radical sites during this process were dissociated by ceric ammonium nitrate. Various factors were optimized and reasonably high level of monomer grafting was achieved, i.e., 15.6%. The effect of different acids as additive and divinyl benzene (DVB) as a cross-linking agent was also studied. Post-grafting sulfonation was conducted to introduce the ionic moieties to the grafted polymer. Ion-exchange capacity (IEC) was measured experimentally and is found to be 1.04 meq g-1, which is in close agreement with the theoretical IEC values. The chemical structure of grafted and functionalized polymer was characterized by attenuated total reflection infrared spectroscopy (ATR-FTIR) and thermal properties were investigated by thermo gravimetric analysis (TGA) and differential scanning calorimetry (DSC). Thermal analysis depicts that the presence of radicals on the polymer chain accelerates the thermal decomposition process. The results signify that the chemical grafting is an effective tool for substantial surface modification and subsequent functionalization of polyethylene.

  11. Disappearance of a low molecular weight heparin fraction (CY 216) differs from standard heparin in rabbits

    Boneu, B.; Buchanan, M.R.; Caranobe, C.; Gabaig, A.M.; Dupouy, D.; Sie, P.; Hirsh, J.

    1987-01-01

    In previous studies, we have reported that standard heparin (SH) was cleared by two mechanisms, a saturable mechanism which predominated at low doses (less than 100 anti-factor Xa U/kg) and a non-saturable mechanism which predominated at higher doses, when the first mechanism became saturated. In this study, we examined the importance of these two mechanisms in the disappearance of a low molecular weight heparin fraction (LMWH) (CY 216), by comparing the pharmacokinetics and the pharmacodynamics of a wide range of doses of SH and CY 216 (1.5 to 500 anti-factor Xa U/kg). Pharmacokinetics was measured as the disappearance of 125 I-radiolabelled SH or CY 216. Pharmacodynamics was measured as the disappearance of the anti-factor Xa activity of SH and CY 216. We found that the saturable mechanism contributed little to the disappearance of CY 216 and that it was cleared predominantly by the non-saturable mechanism at all doses tested. Thus, at low doses (less than 100 anti-factor Xa U/kg), SH was cleared more rapidly than CY 216, whereas at higher doses, CY 216 was cleared more rapidly than SH. We conclude that the mechanism of disappearance of LMWH's differ significantly from those of SH, and that this difference may explain the apparent prolonged anticoagulant activity of LMWH's within the therapeutic range doses

  12. Risk organ preservation technique in reirradiation. Injection of native type high molecular weight hyaluronate

    Kishi, Kazushi; Noda, Yasutaka; Tanaka, Kayo

    2012-01-01

    We developed a practical method of brachytherapy effective for reirradiation, using hyaluronate gel injection to separate the target to be intensively. We intended curative reirradiation with preserving organs at risk. Native-type high molecular weight hyaluronate that has an ideal biologic property to reduce inflammation via inhibitory activity to CD44 and other inflammation receptors was injected to create space during radiotherapy. Rectum, small intestines, skin, and various normal organs are effectively separated and thus eradicative re-irradiation was carried out in safe. We reviewed 55 patients who required the method. There were no complications related to the procedure. Prescribed dose to 100% of the planning target volume (PTV) was 77.93 Gy (range 54-92) equivalent at alpha/beta ratio of 3, with much higher subvolume effect, and the saving effects were enhanced at 3.35 times in the average of those without gel injection. In conclusion, the interventional brachytherapy with hyaluronate gel injection provided 3.35 times safer dose-escalated and eradicative treatment in reirradiation. (author)

  13. Detection of Low Molecular Weight Adulterants in Beverages by Direct Analysis in Real Time Mass Spectrometry.

    Sisco, Edward; Dake, Jeffrey

    2016-04-14

    Direct Analysis in Real Time Mass Spectrometry (DART-MS) has been used to detect the presence of non-narcotic adulterants in beverages. The non-narcotic adulterants that were examined in this work incorporated a number low molecular weight alcohols, acetone, ammonium hydroxide, and sodium hypochlorite. Analysis of the adulterants was completed by pipetting 1 µL deposits onto glass microcapillaries along with an appropriate dopant species followed by introduction into the DART gas stream. It was found that detection of these compounds in the complex matrices of common beverages (soda, energy drinks, etc.) was simplified through the use of a dopant species to allow for adduct formation with the desired compound(s) of interest. Other parameters that were investigated included DART gas stream temperature, in source collision induced dissociation, ion polarity, and DART needle voltage. Sensitivities of the technique were found to range from 0.001 % volume fraction to 0.1 % volume fraction, comparable to traditional analyses completed using headspace gas chromatography mass spectrometry (HS-GC/MS). Once a method was established using aqueous solutions, , fifteen beverages were spiked with each of the nine adulterants, to simulate real world detection, and in nearly all cases the adulterant could be detected either in pure form, or complexed with the added dopant species. This technique provides a rapid way to directly analyze beverages believed to be contaminated with non-narcotic adulterants at sensitivities similar to or exceeding those of traditional confirmatory analyses.

  14. Mapping of low molecular weight heparins using reversed phase ion pair liquid chromatography-mass spectrometry.

    Li, Daoyuan; Chi, Lequan; Jin, Lan; Xu, Xiaohui; Du, Xuzhao; Ji, Shengli; Chi, Lianli

    2014-01-01

    Low molecular weight heparins (LMWHs) are structurally complex, highly sulfated and negatively charged, linear carbohydrate polymers prepared by chemical or enzymatic depolymerization of heparin. They are widely used as anticoagulant drugs possessing better bioavailability, longer half-life, and lower side effects than heparin. Comprehensive structure characterization of LMWHs is important for drug quality assurance, generic drug application, and new drug research and development. However, fully characterization of all oligosaccharide chains in LMWHs is not feasible for current available analytical technologies due to their structure complexity and heterogeneity. Fingerprinting profiling is an efficient way for LMWHs' characterization and comparison. In this work, we present a simple, sensitive, and powerful analytical approach for structural characterization of LMWHs. Two different LMWHs, enoxaparin and nadroparin, were analyzed using reversed phase ion pair electrospray ionization mass spectrometry (RPIP-ESI-MS). More than 200 components were identified, including major structures, minor structures, and process related impurities. This approach is robust for high resolution and complementary fingerprinting analysis of LMWHs. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. High-affinity binding of two molecules of cysteine proteinases to low-molecular-weight kininogen.

    Turk, B.; Stoka, V.; Björk, I.; Boudier, C.; Johansson, G.; Dolenc, I.; Colic, A.; Bieth, J. G.; Turk, V.

    1995-01-01

    Human low-molecular-weight kininogen (LK) was shown by fluorescence titration to bind two molecules of cathepsins L and S and papain with high affinity. By contrast, binding of a second molecule of cathepsin H was much weaker. The 2:1 binding stoichiometry was confirmed by titration monitored by loss of enzyme activity and by sedimentation velocity experiments. The kinetics of binding of cathepsins L and S and papain showed the two proteinase binding sites to have association rate constants kass,1 = 10.7-24.5 x 10(6) M-1 s-1 and kass,2 = 0.83-1.4 x 10(6) M-1 s-1. Comparison of these kinetic constants with previous data for intact LK and its separated domains indicate that the faster-binding site is also the tighter-binding site and is present on domain 3, whereas the slower-binding, lower-affinity site is on domain 2. These results also indicate that there is no appreciable steric hindrance for the binding of proteinases between the two binding sites or from the kininogen light chain. PMID:8528085

  16. [Impact of low-molecular-weight heparin practice guidelines in a geriatric hospital].

    d'Arailh, Lydie; Gaubert-Dahan, Marie-Line; Muller, Florence; Lechowski, Laurent; Teillet, Laurent

    2011-06-01

    The purpose of this study was to assess the impact of good use of anticoagulants guidelines implementation on low molecular weight heparin (LMWH) prescription in a french geriatric hospital. This interventional "before and after" study was conduced by the same geriatrician on a d-day in 2006 and 2009. Guidelines for anticoagulant's prescription based on selected references in the literature was established by an expert's consensus and implemented in 2008. Data were collected in all departments at the Sainte-Perine geriatric hospital for each patient with an LMWH prescription. Assessment was based on quality judgment criteria (indication, dosage, treatment duration, biological monitoring of LMWH). Data were collected for 72 prescriptions prior to the guidelines implementation and for 54 after. Sex-ratio, mean age and percentage of LMWH prescription did not differ significantly between the two periods. There was a better conformity for LMWH dosage prescription (p = 0.002) and biological monitoring prescription (p = 0.036) after the guidelines implementation. Conformity of LMWH indication and treatment duration were improved but the difference remained not significant (respectively p = 0.49 and p = 0.80). Implementing guidelines for LMWH use in geriatrics can improve quality of prescription. The impact was effective but limited. These guidelines are now in general use in the Sainte-Perine hospital.

  17. [Effects of low molecular weight organic acids on redox reactions of mercury].

    Zhao, Shi-Bo; Sun, Rong-Guo; Wang, Ding-Yong; Wang, Xiao-Wen; Zhang, Cheng

    2014-06-01

    To study the effects of the main component of vegetation root exudates-low molecular weight organic acids on the redox reactions of mercury, laboratory experiments were conducted to investigate the roles of tartaric, citric, and succinic acid in the redox reactions of mercury, and to analyze their interaction mechanism. The results indicated that tartaric acid significantly stimulated the mercury reduction reaction, while citric acid had inhibitory effect. Succinic acid improved the reduction rate at low concentration, and inhibited the reaction at high concentration. The mercury reduction rate by tartaric acid treatment was second-order with respect to Hg2+ concentration, ranging from 0.0014 L x (ng x min)(-1) to 0.005 6 L x (ng x min)(-1). All three organic acids showed a capacity for oxidating Hg(0) in the early stage, but the oxidized Hg(0) was subsequently reduced. The oxidation capacity of the three organic acids was in the order of citric acid > tartaric acid > succinic acid.

  18. Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants.

    Simal-Gándara, J; Sarria-Vidal, M; Koorevaar, A; Rijk, R

    2000-08-01

    The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 microns-thick oriented PP) into the food stimulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.

  19. Crystal structure and putative substrate identification for the Entamoeba histolytica low molecular weight tyrosine phosphatase.

    Linford, Alicia S; Jiang, Nona M; Edwards, Thomas E; Sherman, Nicholas E; Van Voorhis, Wesley C; Stewart, Lance J; Myler, Peter J; Staker, Bart L; Petri, William A

    2014-01-01

    Entamoeba histolytica is a eukaryotic intestinal parasite of humans, and is endemic in developing countries. We have characterized the E. histolytica putative low molecular weight protein tyrosine phosphatase (LMW-PTP). The structure for this amebic tyrosine phosphatase was solved, showing the ligand-induced conformational changes necessary for binding of substrate. In amebae, it was expressed at low but detectable levels as detected by immunoprecipitation followed by immunoblotting. A mutant LMW-PTP protein in which the catalytic cysteine in the active site was replaced with a serine lacked phosphatase activity, and was used to identify a number of trapped putative substrate proteins via mass spectrometry analysis. Seven of these putative substrate protein genes were cloned with an epitope tag and overexpressed in amebae. Five of these seven putative substrate proteins were demonstrated to interact specifically with the mutant LMW-PTP. This is the first biochemical study of a small tyrosine phosphatase in Entamoeba, and sets the stage for understanding its role in amebic biology and pathogenesis. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Patient compliance with extended low molecular weight heparin injections following hip and knee arthroplasty.

    Deakin, Dan E; Mishreki, Andrew; Aslam, Nadim; Docker, Charles

    2010-01-01

    The use of extended duration thromboprophylaxis following hip and knee arthroplasty is becoming widespread. The aim of our study was to determine patient compliance with extended duration thromboprophylaxis using low molecular weight (LMWH) injections following hip and knee arthroplasty. 42 consecutive patients undergoing hip and knee arthroplasty were prospectively contacted during their fifth post operative week. A fully anonymised questionnaire was completed by each patient. All patients responded. One was excluded having been prescribed warfarin for pre existing atrial fibrillation. Twenty nine (71%) patients were discharged with the intention of self administering LMWH injections. Eight (20%) and four (9%) patients were discharged with the intention of administration by a relative or district nurse respectively. No patient required the person administering the injections to be changed after discharge from hospital. 90% (n=37) of patients reported not missing any doses. 10% (n=2) of patients missed one dose and 10% (n=2) missed two doses. Patient compliance with extended duration thromboprophylaxis using LMWH injections is extremely high. Oral thromboprophylaxis may be useful in the minority of patients requiring daily visits by a nurse to administer injections.

  1. Feline urine metabolomic signature: characterization of low-molecular-weight substances in urine from domestic cats.

    Rivera-Vélez, Sol-Maiam; Villarino, Nicolas F

    2018-02-01

    Objectives This aim of this study was to characterize the composition and content of the feline urine metabolome. Methods Eight healthy domestic cats were acclimated at least 10 days before starting the study. Urine samples (~2 ml) were collected by ultrasound-guided cystocentesis. Samples were centrifuged at 1000 × g for 8 mins, and the supernatant was analyzed by gas chromatography/time-of-flight mass spectrometery. The urine metabolome was characterized using an untargeted metabolomics approach. Results Three hundred and eighteen metabolites were detected in the urine of the eight cats. These molecules are key components of at least 100 metabolic pathways. Feline urine appears to be dominated by carbohydrates, carbohydrate conjugates, organic acid and derivatives, and amino acids and analogs. The five most abundant molecules were phenaceturic acid, hippuric acid, pseudouridine phosphate and 3-(4-hydroxyphenyl) propionic acid. Conclusions and relevance This study is the first to characterize the feline urine metabolome. The results of this study revealed the presence of multiple low-molecular-weight substances that were not known to be present in feline urine. As expected, the origin of the metabolites detected in urine was diverse, including endogenous compounds and molecules biosynthesized by microbes. Also, the diet seemed to have had a relevant role on the urine metabolome. Further exploration of the urine metabolic phenotype will open a window for discovering unknown, or poorly understood, metabolic pathways. In turn, this will advance our understanding of feline biology and lead to new insights in feline physiology, nutrition and medicine.

  2. Laser surface modification of ultra-high-molecular-weight polyethylene (UHMWPE) for biomedical applications

    Riveiro, A., E-mail: ariveiro@uvigo.es [Applied Physics Department, University of Vigo, ETSII, Lagoas-Marcosende, 9, Vigo 36310 (Spain); Centro Universitario de la Defensa, Escuela Naval Militar, Plaza de España 2, 36920 Marín (Spain); Soto, R.; Val, J. del; Comesaña, R.; Boutinguiza, M.; Quintero, F.; Lusquiños, F.; Pou, J. [Applied Physics Department, University of Vigo, ETSII, Lagoas-Marcosende, 9, Vigo 36310 (Spain)

    2014-05-01

    Ultra-high-molecular-weight polyethylene (UHMWPE) is a synthetic polymer used for biomedical applications because of its high impact resistance, ductility and stability in contact with physiological fluids. Therefore, this material is being used in human orthopedic implants such as total hip or knee replacements. Surface modification of this material relates to changes on its chemistry, microstructure, roughness, and topography, all influencing its biological response. Surface treatment of UHMWPE is very difficult due to its high melt viscosity. This work presents a systematic approach to discern the role of different laser wavelengths (λ = 1064, 532, and 355 nm) on the surface modification of carbon coated UHMWPE samples. Influence of laser processing conditions (irradiance, pulse frequency, scanning speed, and spot overlapping) on the surface properties of this material was determined using an advanced statistical planning of experiments. A full factorial design of experiments was used to find the main effects of the processing parameters. The obtained results indicate the way to maximize surface properties which largely influence cell–material interaction.

  3. Aspect of use of ultrahigh molecular weight polyethylene (uhmwpe) as biomaterial and as armour material (abstract)

    Fuzail, M.

    2011-01-01

    Among the known polymeric materials, ultrahigh molecular weight polyethylene (UHMWPE) has unique properties as a biomaterial as well as armour material. Its high strength and very high modulus makes it an alternate candidate as body armour for example bullet proof vest. The drawn fibers from this material are best known for their break strength and compete with the steel and carbon fibers. On the other hand, its extremely high molar mass imparts outstanding wear resistance and impact toughness better than any other polymer which makes it a better choice as biomaterial used in hip and knee transplants. As a biomaterial, when body transplants are gamma sterilized, their shelf life depends upon the number and nature of free radicals produced during sterilization. These long-lived radicals ultimately affect the wear properties of hip and knee transplants. The Electron Spin Resonance (ESR) technique used to determine the concentration and nature of free radicals in about 16 years old powder, fibers and ram-extruded bar samples shows that at low microwave power (0.01 mW), polyenyl radicals become prominent while at high microwave power (160 mW), oxygen-centered radicals show their identity. The ESR study also exhibits that the concentration of free radicals depends upon the crystallinities of different morphologies known i.e powder, extruded bars and drawn fibers. Differential scanning calorimetry shows the order of crystallinity as: fiber > extruded bars > powder. (author)

  4. Purification, partial characterization, and immunological relationships of multiple low molecular weight protease inhibitors of soybean

    Hwang, D L.R.; Lin, K T.D.; Yang, W K; Foard, D E

    1977-01-01

    Five protease inhibitors, I-V, in the molecular weight range 7000-8000 were purified from Tracy soybeans by ammonium sulfate precipitation, gel filtration on Sephadex G-100 and G-75, and column chromatography on DEAE-cellulose. In common with previously described trypsin inhibitors from legumes, I-V have a high content of half-cystine and lack tryptophan. By contrast with other legume inhibitors, inhibitor II contains 3 methionine residues. Isoelectric points range from 6.2 to 4.2 in order from inhibitor I to V. Molar ratios (inhibitor/enzyme) for 50% trypsin inhibition are I = 4.76, II = 1.32, III = 3.22, IV = 2.17, V = 0.97. Only V inhibits chymotrypsin significantly (molar ratio = 1.33 for 50% inhibition). The sequence of the first 16 N-terminal amino acid residues of inhibitor V is identical to that of the Bowman-Birk inhibitor; all other observations also indicate that inhibitor V and Bowman-Birk are identical. The first 20 N-terminal amino acid residues of inhibitor II show high homology to those of Bowman-Birk inhibitor, differing by 1 deletion and 5 substitutions. Immunological tests show that inhibitors I through IV are fully cross-reactive with each other but are distinct from inhibitor V.

  5. AWE-WQ: fast-forwarding molecular dynamics using the accelerated weighted ensemble.

    Abdul-Wahid, Badi'; Feng, Haoyun; Rajan, Dinesh; Costaouec, Ronan; Darve, Eric; Thain, Douglas; Izaguirre, Jesús A

    2014-10-27

    A limitation of traditional molecular dynamics (MD) is that reaction rates are difficult to compute. This is due to the rarity of observing transitions between metastable states since high energy barriers trap the system in these states. Recently the weighted ensemble (WE) family of methods have emerged which can flexibly and efficiently sample conformational space without being trapped and allow calculation of unbiased rates. However, while WE can sample correctly and efficiently, a scalable implementation applicable to interesting biomolecular systems is not available. We provide here a GPLv2 implementation called AWE-WQ of a WE algorithm using the master/worker distributed computing WorkQueue (WQ) framework. AWE-WQ is scalable to thousands of nodes and supports dynamic allocation of computer resources, heterogeneous resource usage (such as central processing units (CPU) and graphical processing units (GPUs) concurrently), seamless heterogeneous cluster usage (i.e., campus grids and cloud providers), and support for arbitrary MD codes such as GROMACS, while ensuring that all statistics are unbiased. We applied AWE-WQ to a 34 residue protein which simulated 1.5 ms over 8 months with peak aggregate performance of 1000 ns/h. Comparison was done with a 200 μs simulation collected on a GPU over a similar timespan. The folding and unfolded rates were of comparable accuracy.

  6. The influence of magnetic field on ballistic performance of aramid fibre and ultrahigh molecular weight polyethylene

    Wong, Y.C.; Ruan, D.; Sesso, M.L.

    2014-01-01

    Highlights: • Ballistic tests conducted on Kevlar and UHMWPE within a magnetic field. • Repulsion force created by opposing magnet poles reduced the impact momentum. • High speed camera images showed no perforation on Kevlar due to magnetic field. • Standoff distance between magnets has an effect on the repulsion force. - Abstract: An innovative method is introduced here whereby using two sets of arrays of rare earth magnets aligned opposite each other in order to create a repulsion force owing to the like poles when facing close to each other. Ballistic test samples of aramid fibre (Kevlar K29) and ultrahigh molecular weight polyethylene (UHMWPE) were sandwiched by two sets of opposing magnets. Ballistic test was conducted using a gas gun with a 7.62 mm diameter projectile at a velocity ranging from 160 to 220 m/s. High speed camera was used to capture the ballistics testing and it shows that the magnetic repulsion force created by the opposing rare earth magnets managed to suppress the projectile from advancing into the front face of the aramid fibre. Similarly, when magnets were used, the UHMWPE sample shows the projectile perforated through the first few sheets and finally rested on the last sheet showing partial perforation

  7. Higher molecular weight dissolved organic nitrogen turnover as affected by soil management history

    Lønne Enggrob, Kirsten

    of different management histories on the turnover of high Mw DON. Further, we distinguished between several classes of high Mw DON, i.e., 1-10 kDa and >10 kDa. 3. Materials and methods With the use of micro-lysimeters, the turnover of triple-labeled (15N, 14C and 13C) high Mw DON was studied in a sandy soil......High molecular weight dissolved organic nitrogen turnover as affected by soil management history *Kirsten Lønne Enggrob,1 Lars Elsgaard,1 and Jim Rasmussen1 1Aarhus University, Dept. of Agroecology, Foulum, Denmark 1. Introduction Dissolved organic nitrogen (DON) play an important role in soil N...... are presented for 14CO2 evolution during 14 days of incubation. 4. Results and conclusion Results showed that the turnover rate of high Mw DON was dependent on both the Mw size of DON and on the soil liming history. Evidence showing where in the DON Mw sizes the bottleneck lies will be presented....

  8. Assembled microneedle arrays enhance the transport of compounds varying over a large range of molecular weight across human dermatomed skin

    Verbaan, F.J.; Bal, S.M.; van den Berg, D.J.; Groenink, W.H.H.; Verpoorten, H.; Lüttge, Regina; Bouwstra, J.A.

    2007-01-01

    In this study, we demonstrate the feasibility to use microneedle arrays manufactured from commercially available 30G hypodermal needles to enhance the transport of compounds up to a molecular weight of 72 kDa. Piercing of human dermatomed skin with microneedle arrays was studied by Trypan Blue

  9. Molecular Weights of Bovine and Porcine Heparin Samples: Comparison of Chromatographic Methods and Results of a Collaborative Survey

    Sabrina Bertini

    2017-07-01

    Full Text Available In a collaborative study involving six laboratories in the USA, Europe, and India the molecular weight distributions of a panel of heparin sodium samples were determined, in order to compare heparin sodium of bovine intestinal origin with that of bovine lung and porcine intestinal origin. Porcine samples met the current criteria as laid out in the USP Heparin Sodium monograph. Bovine lung heparin samples had consistently lower average molecular weights. Bovine intestinal heparin was variable in molecular weight; some samples fell below the USP limits, some fell within these limits and others fell above the upper limits. These data will inform the establishment of pharmacopeial acceptance criteria for heparin sodium derived from bovine intestinal mucosa. The method for MW determination as described in the USP monograph uses a single, broad standard calibrant to characterize the chromatographic profile of heparin sodium on high-resolution silica-based GPC columns. These columns may be short-lived in some laboratories. Using the panel of samples described above, methods based on the use of robust polymer-based columns have been developed. In addition to the use of the USP’s broad standard calibrant for heparin sodium with these columns, a set of conditions have been devised that allow light-scattering detected molecular weight characterization of heparin sodium, giving results that agree well with the monograph method. These findings may facilitate the validation of variant chromatographic methods with some practical advantages over the USP monograph method.

  10. Rapid Analysis of Apolar Low Molecular Weight Constituents in Wood Using High Pressure Liquid Chromatography with Evaporative Light Scattering Detection

    Claassen, F.W.; Haar, van de C.; Beek, van T.A.; Dorado, J.; Martinez-Inigo, M.; Sierra-Alvarez, R.

    2000-01-01

    A new high pressure liquid chromatographic method with evaporative light scattering detection was developed for the qualitative and quantitative analysis of apolar, low molecular weight constituents in wood. The wood extractives were obtained by means of a 6 h Soxhlet extraction with acetone. The

  11. Influence of low-molecular-weight glutenin subunit haplotypes on dough rheology and baking quality in elite common wheat varieties

    The low molecular weight glutenin subunits (LMW-GSs) are a class of wheat seed storage proteins directly involved in the formation of gluten. Depending on the first amino acid residue of the mature proteins, the LMW-GSs are divided into methionine, serine or isoleucine type. These proteins are encod...

  12. Development of gel-filter method for high enrichment of low-molecular weight proteins from serum.

    Lingsheng Chen

    Full Text Available The human serum proteome has been extensively screened for biomarkers. However, the large dynamic range of protein concentrations in serum and the presence of highly abundant and large molecular weight proteins, make identification and detection changes in the amount of low-molecular weight proteins (LMW, molecular weight ≤ 30kDa difficult. Here, we developed a gel-filter method including four layers of different concentration of tricine SDS-PAGE-based gels to block high-molecular weight proteins and enrich LMW proteins. By utilizing this method, we identified 1,576 proteins (n = 2 from 10 μL serum. Among them, 559 (n = 2 proteins belonged to LMW proteins. Furthermore, this gel-filter method could identify 67.4% and 39.8% more LMW proteins than that in representative methods of glycine SDS-PAGE and optimized-DS, respectively. By utilizing SILAC-AQUA approach with labeled recombinant protein as internal standard, the recovery rate for GST spiked in serum during the treatment of gel-filter, optimized-DS, and ProteoMiner was 33.1 ± 0.01%, 18.7 ± 0.01% and 9.6 ± 0.03%, respectively. These results demonstrate that the gel-filter method offers a rapid, highly reproducible and efficient approach for screening biomarkers from serum through proteomic analyses.

  13. Influence of Low Molecular Weight Organic Acids on Transport of Cadmium and Copper Ions across Model Phospholipid Membranes

    Parisová, Martina; Navrátil, Tomáš; Šestáková, Ivana; Jaklová Dytrtová, Jana; Mareček, Vladimír

    2013-01-01

    Roč. 8, č. 1 (2013), s. 27-44 ISSN 1452-3981 R&D Projects: GA AV ČR IAA400400806 Institutional support: RVO:61388963 ; RVO:61388955 Keywords : cadmium * copper * low molecular weight organic acid Subject RIV: CG - Electrochemistry Impact factor: 1.956, year: 2013

  14. Vitamin K antagonists or low-molecular-weight heparin for the long term treatment of symptomatic venous thromboembolism

    van der Heijden, J. F.; Hutten, B. A.; Büller, H. R.; Prins, M. H.

    2000-01-01

    Patients who have had an episode of symptomatic venous thromboembolism are usually treated for at least five days with intravenous unfractionated heparin or subcutaneous low-molecular-weight heparin. Thereafter, they received a three month course of a vitamin K antagonist, with a dose adjusted to

  15. Topochemical approach to efficiently produce main-chain poly(bile acid)s with high molecular weights.

    Li, Weina; Li, Xuesong; Zhu, Wei; Li, Changxu; Xu, Dan; Ju, Yong; Li, Guangtao

    2011-07-21

    Based on a topochemical approach, a strategy for efficiently producing main-chain poly(bile acid)s in the solid state was developed. This strategy allows for facile and scalable synthesis of main-chain poly(bile acid)s not only with high molecular weights, but also with quantitative conversions and yields.

  16. Molecular Weights of Bovine and Porcine Heparin Samples: Comparison of Chromatographic Methods and Results of a Collaborative Survey.

    Bertini, Sabrina; Risi, Giulia; Guerrini, Marco; Carrick, Kevin; Szajek, Anita Y; Mulloy, Barbara

    2017-07-19

    In a collaborative study involving six laboratories in the USA, Europe, and India the molecular weight distributions of a panel of heparin sodium samples were determined, in order to compare heparin sodium of bovine intestinal origin with that of bovine lung and porcine intestinal origin. Porcine samples met the current criteria as laid out in the USP Heparin Sodium monograph. Bovine lung heparin samples had consistently lower average molecular weights. Bovine intestinal heparin was variable in molecular weight; some samples fell below the USP limits, some fell within these limits and others fell above the upper limits. These data will inform the establishment of pharmacopeial acceptance criteria for heparin sodium derived from bovine intestinal mucosa. The method for MW determination as described in the USP monograph uses a single, broad standard calibrant to characterize the chromatographic profile of heparin sodium on high-resolution silica-based GPC columns. These columns may be short-lived in some laboratories. Using the panel of samples described above, methods based on the use of robust polymer-based columns have been developed. In addition to the use of the USP's broad standard calibrant for heparin sodium with these columns, a set of conditions have been devised that allow light-scattering detected molecular weight characterization of heparin sodium, giving results that agree well with the monograph method. These findings may facilitate the validation of variant chromatographic methods with some practical advantages over the USP monograph method.

  17. Flexible mechanoprosthesis made from woven ultra-high-molecular-weight polyethylene fibres: proof of concept in a chronic sheep model

    Basir, Amir; Grobben, Remco B.; Cramer, Maarten Jan; van Herwaarden, Joost A.; Vink, Aryan; Pasterkamp, Gerard; Kluin, Jolanda; Gründeman, Paul F.

    2017-01-01

    OBJECTIVES: Ultra-high-molecular-weight polyethylene (UHMWPE) fibres are flexible, have high tensile strength, and platelet and bacterial adhesion is low. Therefore, UHMWPE may overcome limitations of current mechanical valves and bioprostheses. In this study, the bio-compatibility and functionality

  18. The prevalence of Type 2 diabetes is not increased in normal-weight women with PCOS.

    Pelanis, Rasa; Mellembakken, Jan Roar; Sundström-Poromaa, Inger; Ravn, Pernille; Morin-Papunen, Laure; Tapanainen, Juha S; Piltonen, Terhi; Puurunen, Johanna; Hirschberg, Angelica Lindén; Fedorcsak, Peter; Andersen, Marianne; Glintborg, Dorte

    2017-11-01

    Is oral glucose tolerance test (OGTT) needed in all women with polycystic ovary syndrome (PCOS)? OGTT is not routinely needed in women with PCOS and BMI PCOS is associated with insulin resistance and increased prevalence of prediabetes and Type 2 diabetes (T2D) which is closely linked to obesity and possibly age, ethnicity and PCOS phenotype. Several guidelines recommend OGTT upon diagnosis of PCOS and during follow-up. A Nordic cross-sectional study including 876 women. The 876 Nordic women with PCOS, aged 14-57 years, were examined for T2D and prediabetes (impaired glucose tolerance [IGT] or impaired fasting glucose (IFG) by OGTT. Of all study subjects 3% (23/876) had T2D, 23% (204/876) prediabetes and 74% (649/876) had normal glucose tolerance (NGT). Increased BMI and waist circumference were significantly (P PCOS phenotype did not predict 2-h glucose levels during OGTT after adjustment for BMI and age. The present study included cross-sectional data and prospective studies are needed to confirm our results. These results may not apply to populations of other ethnic origin. Routine OGTT may not be indicated in normal-weight women with PCOS. None. N/A. © The Author 2017. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

  19. Effects of low molecular weight heparin on the polarization and cytokine profile of macrophages and T helper cells in vitro.

    Bruno, Valentina; Svensson-Arvelund, Judit; Rubér, Marie; Berg, Göran; Piccione, Emilio; Jenmalm, Maria C; Ernerudh, Jan

    2018-03-08

    Low molecular weight heparin (LMWH) is widely used in recurrent miscarriage treatment. The anti-coagulant effects are established, while immunological effects are not fully known. Our aim was to assess LMWH effects on activation and polarization of central regulatory immune cells from healthy women, and on placenta tissues from women undergoing elective abortions. Isolated blood monocytes and T helper (Th) cells under different activation and polarizing conditions were cultured with or without LMWH. Flow cytometry showed that LMWH exposure induced increased expression of HLA-DR and CD206 in macrophages. This phenotype was associated with increased secretion of Th17-associated CCL20, and decreased secretion of CCL2 (M2-associated) and CCL22 (Th2), as measured by multiplex bead array. In accordance, LMWH exposure to Th cells reduced the proportion of CD25highFoxp3+ regulatory T-cells, intensified IFN-γ secretion and showed a tendency to increase the lymphoblast proportions. Collectively, a mainly pro-inflammatory effect was noted on two essential tolerance-promoting cells. Although the biological significancies of these in vitro findings are uncertain and need to be confirmed in vivo, they suggest the possibility that immunological effects of LMWH may be beneficial mainly at an earlier gestational age to provide an appropriate implantation process in women with recurrent miscarriage.

  20. Sugar Composition and Molecular Weight Distribution of Cell Wall Polysaccharides in Outer and Inner Tissues from Segments of Dark Grown Squash (Cucurbita maxima Duch.) Hypocotyls.

    Wakabayashi, K; Sakurai, N; Kuraishi, S

    1990-07-01

    The elongation growth of stem segments is determined by the outer cell layers (epidermis and collenchyma). We measured the sugar composition and molecular weight distribution of pectin and hemicellulose fractions obtained from inner and outer tissues of squash (Cucurbita maxima Duch.) hypocotyls. In addition, we studied the changes in these parameters after a 9 hour period of incubation of the segments. The results show that outer tissues have higher molecular weight pectin and hemicellulose compared to inner tissues (2-3 times higher). Incubation results in a 13 to 25% decrease in the amount of pectin and hemicellulose in inner tissues and an increase of 11 to 32% in the outer tissues. This increase in the outer tissues is accompanied by a decrease in the molecular weight of some of the components. These results clearly show that cell wall metabolism during elongation growth differs markedly in inner and outer tissues, and that future studies on the effect of auxin need to take these differences into account.