Influence of pretreatment on AMWD (apparent molecular weight distribution) of dissolved organics in the secondary effluent and membrane structure parameter model analysis for ultrafiltration

2006 ◽  
Vol 6 (4) ◽  
pp. 99-106
Author(s):  
L. Wang ◽  
X.D. Wang ◽  
J.T. Chai ◽  
Y. Kang
Keyword(s):  
Molecular Weight ◽  
Pore Size ◽  
High Molecular Weight ◽  
Membrane Structure ◽  
Apparent Molecular Weight ◽  
Low Molecular Weight ◽  
Secondary Effluent ◽  
Structure Parameter ◽  
Pore Density ◽  
The Mean

This study analyzed the characteristics of the apparent molecular weight distribution (AMWD) of the secondary effluent organic matter and investigated the effect of various applicable pretreatment technologies for ultrafiltration (UF), including coagulation, powdered activity carbon (PAC) adsorption and O3-PAC process, on the AMWD of effluent and the flux decline. The influence of molecular size distribution on the mean pore size and pore density of membrane was then evaluated with the model of membrane structure parameter. The results showed: (1) after different pretreatments, the AMWD of raw water changed, coagulation could effectively remove high molecular weight organics, PAC adsorption was effective in removing low molecular weight organics, due to ozonization and PAC adsorption and O3-PAC pretreatment could remove both high molecular weight and low molecular weight organics; (2) the AMWD had great influence on membrane permeation, after different pretreatments, the AMWD of raw water changed and the variation of membrane permeation was also different; (3) the influence factors a1and a2 of the mean pore size and the membrane pore density of different pretreatment water samples were used as indexes which calculated through experiment and the model of membrane structure parameter. The influence of AMWD in water samples on the membrane mean pore size and pore density were then evaluated, which showed that low molecular weight organics could easily cause interior adsorption, and high molecular weight organics could easily cause membrane surface blocking.

Subcellular Distribution of Low- and High Molecular-Weight Renin and its Relation to a Renin Inhibitor in Pig Renal Cortex

1980 ◽  
Vol 59 (5) ◽  
pp. 337-345 ◽  
Author(s):  
G. A. Sagnella ◽  
P. R. B. Caldwell ◽  
W. S. Peart
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Subcellular Distribution ◽  
Renal Cortex ◽  
Soluble Fraction ◽  
Gel Filtration ◽  
Apparent Molecular Weight ◽  
Main Peak ◽  
Low Molecular Weight ◽  
Molecular Weight Form

1. The subcellular distribution of low-molecular-weight and high-molecular weight forms of pig renin has been investigated. 2. Renin, in aqueous extracts of a ‘renin granular fraction’ prepared by differential centrifugation, after gel filtration on Sephadex G-100 displayed an apparent molecular weight of 40 000 and was not activated by acidification to pH 2.8. 3. Renin in the soluble fraction separated on Sephadex G-100 at neutral pH displayed a main peak of activity with an apparent molecular weight of 40000. When eluates were acidified to pH 2.8 (2°C, 60 min) a marked increase in renin activity was observed in the region corresponding to an apparent molecular weight of 50 000. 4. A renin inhibitory material was isolated from the soluble fraction by DEAE chromatography. This material displayed an apparent molecular weight of 50000 and it was destroyed by acidification to pH 2.8. 5. The presence of the proteolytic inhibitor N-ethylmaleimide yielded an apparently high-molecular-weight form of renin (60000–70000) from the soluble fraction, but this was not found in the granular fraction. 6. We conclude that pig renal renin is stored within membrane-bounded subcellular organelles as the low-molecular-weight form. High-molecular-weight renin and renin inhibitory activity are localized to the cortical soluble fraction. In addition, the soluble fraction contains a material which in the presence of N-ethylmaleimide results in the formation of an apparently high-molecular-weight renin.

Interconversion between High- and Low-Molecular-Weight Forms of Renin in Dog Kidney

1980 ◽  
Vol 59 (s6) ◽  
pp. 25s-27s ◽  
Author(s):  
K. Yamamoto ◽  
F. Ikemoto ◽  
M. Kawamura ◽  
K. Takaori
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Apparent Molecular Weight ◽  
Kidney Cortex ◽  
Low Molecular Weight ◽  
Cytosol Fraction ◽  
High Molecular Weight Form ◽  
Binding Substance ◽  
Dog Kidney ◽  
Molecular Weight Form

1. The low-molecular-weight (40 000) form of renin was converted into the high-molecular-weight (60 000) form of renin with sulphydryl oxidation, and the high-molecular-weight form of renin was re-converted into the low-molecular-weight form with a reduction of disulphide bonds in the renal cortical homogenate of the dog. Therefore, the low- and high-molecular-weight forms of renin were interconvertible. 2. The formation of high-molecular-weight form of renin required a renin binding substance which was found to be included in the cytosol fraction of kidney cortex of the dog. 3. The renin binding substance of the dog was unstable to heat and low pH, but vitally resistant to Triton X-100 and chloroform. It did not bind to concanavalin A Sepharose 4B. 4. The renin binding substance was eluted in the molecular-weight region between 156 000 and 60 000 on Sephadex G-200, and such apparent molecular weight was not altered by urea at 4 mol/l; thus molecular weight greater than the theoretically expected value of 20 000 was indicated.

The Effect of Dextran of Various Molecular Weight on the Coagulation in Dogs

1961 ◽  
Vol 06 (01) ◽  
pp. 015-024 ◽  
Author(s):  
Sven Erik Bergentz ◽  
Oddvar Eiken ◽  
Inga Marie Nilsson
Keyword(s):  
Molecular Weight ◽  
Body Weight ◽  
High Molecular Weight ◽  
Bleeding Time ◽  
Factor Vii ◽  
Low Molecular Weight ◽  
Factor V ◽  
Coagulation Mechanism ◽  
Coagulation Defects

Summary1. Infusions of low molecular weight dextran (Mw = 42 000) to dogs in doses of 1—1.5 g per kg body weight did not produce any significant changes in the coagulation mechanism.2. Infusions of high molecular weight dextran (Mw = 1 000 000) to dogs in doses of 1—1.5 g per kg body weight produced severe defects in the coagulation mechanism, namely prolongation of bleeding time and coagulation time, thrombocytopenia, pathological prothrombin consumption, decrease of fibrinogen, prothrombin and factor VII, factor V and AHG.3. Heparin treatment of the dogs was found to prevent the decrease of fibrinogen, prothrombin and factor VII, and factor V otherwise occurring after injection of high molecular weight dextran. Thrombocytopenia was not prevented.4. In in vitro experiments an interaction between fibrinogen and dextran of high and low molecular weight was found to take place in systems comprising pure fibrinogen. No such interaction occurred in the presence of plasma.5. It is concluded that the coagulation defects induced by infusions of high molecular weight dextran are due to intravascular coagulation.

scholarly journals Effect of ageing on plasma lipoprotein(a) levels

2002 ◽  
Vol 39 (3) ◽  
pp. 237-240 ◽  
Author(s):  
Harukuni Akita ◽  
Miyao Matsubara ◽  
Hitoshi Shibuya ◽  
Hirotoshi Fuda ◽  
Hitoshi Chiba
Keyword(s):  
Molecular Weight ◽  
Coronary Heart Disease ◽  
Risk Factor ◽  
Heart Disease ◽  
The Elderly ◽  
Low Molecular Weight ◽  
Lipoprotein A ◽  
Significant Difference ◽  
The Mean ◽  
Japanese Subjects

Background Lipoprotein(a) [Lp(a)] is a risk factor for atherosclerosis and increases with age. The purpose of this study was to determine the effect of ageing on Lp(a) for three different apo(a) phenotypes. Methods We measured plasma Lp(a) concentrations in 551 unrelated Japanese subjects (20-88 years of age). We performed statistical analyses separately for three apo(a) phenotypes: the low-molecular-weight (LMW) phenotype with the F, B or S1 isoform, the intermediate-molecular-weight (IMW) phenotype with the S2 isoform and the high-molecular-weight (HMW) phenotype with the S3 or S4 isoform. Results For each phenotype, the mean plasma Lp(a) concentration and the frequency of Lp(a) concentrations ≥ 250 mg/L increased with age. Further, a statistically significant difference was always found between the younger subjects (20-39 years of age) and the elderly (over 60 years). The frequency of coronary heart disease increased with age, particularly for the LMW and IMW phenotypes. Conclusions We conclude that ageing elevates plasma Lp(a) concentrations, which may have a role in the prevalence of coronary heart disease in the elderly, especially those with the LMW or IMW phenotypes.

scholarly journals Antiparasitic antibodies occur with similar frequency in patients with clinically established multiple sclerosis with or without oligoclonal bands in the cerebrospinal fluid

2013 ◽  
Vol 71 (8) ◽  
pp. 512-515 ◽  
Author(s):  
Fabiana Cruz Gomes da Fonseca-Papavero ◽  
Dagoberto Callegaro ◽  
Paulo Diniz da Gama ◽  
Jose Antonio Livramento ◽  
Adelaide Jose Vaz ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Hygiene Hypothesis ◽  
Oligoclonal Bands ◽  
Parasitic Infections ◽  
Low Molecular Weight ◽  
Serum Samples ◽  
Similar Frequency ◽  
Electrophoresis Of Proteins

The "hygiene hypothesis" postulates an inverse relationship between the prevalence of parasitic infections and the frequency of multiple sclerosis (MS). Objective: It was to study whether antibodies against parasites could be demonstrated more frequently in blood serum from MS patients with oligoclonal bands (OCB) than from MS patients without OCB. Methods: We studied serum samples from 164 patients who had previously been analyzed to investigate OCB. Parasitic antibodies were studied through unidimensional electrophoresis of proteins on polyacrylamide gel against Taenia antigens, searching for antiparasitic specific low molecular weight antibodies and also for antiparasitic nonspecific high molecular weight antibodies. Results: Two of the 103 patients with no evidence of OCB had antibodies of low molecular weight and 59 of them had antibodies of high molecular weight. Of the 61 patients with evidence of OCB, one showed antibodies of low molecular weight and 16 showed antibodies of high molecular weight. Conclusion: Antiparasitic antibodies are detected with similar frequency in MS patients with OCB and in MS patients without OCB.

scholarly journals Evaluation and Management of Women who Have Experienced Stillbirth in Their Previous Pregnancies

2019 ◽  
pp. 1
Author(s):  
Erdem Fadiloglu ◽  
Atakan Tanacan ◽  
Canan Unal ◽  
Mehmet Sinan Beksac
Keyword(s):  
Risk Factors ◽  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Low Dose ◽  
Methylenetetrahydrofolate Reductase ◽  
Post Partum ◽  
Subsequent Pregnancy ◽  
Low Molecular Weight ◽  
Mthfr Polymorphisms ◽  
The Mean

<p><strong>Objective:</strong> To evaluate the subsequent pregnancy outcomes of women who have experienced unexplained stillbirth in their previous gestations.</p><p><strong>Study Design:</strong> This retrospective cohort consisted of 14 pregnancies who had stillbirth (without known risk factors) in their previous pregnancies. These patients had been included in a special preconceptional care program to be evaluated in terms of etiological risk factors for stillbirth. At least one of the risk factors, such as methylenetetrahydrofolate reductase (MTHFR) polymorphisms, hereditary thrombophilias and autoimmune problems, were defined in this study population. After detection of pregnancy, the patients were administered low-dose low-molecular-weight heparin (LMWH) (enoxaparin, 1×2000 Anti-XA IU/0.2 mL/day), low-dose salicylic acid (100 mg/day) and low-dose corticosteroid (methylprednisolone, 1×4 mg/day orally) in necessary cases.</p><p><strong>Results:</strong> Out of 14 pregnancies, 4 (28.5%) ended up with miscarriages at 9, 11, 11 and 15 gestational weeks, respectively. The remaining 10 pregnancies ended up with alive deliveries. The mean gestational week at birth was 36.4±0.51, while the mean birthweight was 2882±381.01 g. Out of 10 pregnancies, only one was diagnosed as IUGR. Only two newborn necessitated hospitalization in the neonatal intensive care unit (NICU) due to respiratory problems. Both newborns were discharged from the NICU without any further complication at the post-partum 5th day. </p><p><strong>Conclusion:</strong> Patients with a prior stillbirth should be screened for MTHFR polymorphisms, autoimmune problems and hereditary thrombophilias, especially in case of absence of any etiological factor. Management of these patients with low-dose aspirin, low-dose low molecular weight heparin and corticosteroids seemed to be beneficial for increasing live birth rates and avoiding obstetric complications.</p>

Microporous Bio-Membrane Materials Based on High Molecular Weight Polylactide and Low Molecular Weight Poly(ethylene glycol)

2012 ◽  
Vol 567 ◽  
pp. 123-126
Author(s):  
Teng Fei Shen ◽  
Man Geng Lu ◽  
Li Yan Liang
Keyword(s):  
Molecular Weight ◽  
Ethylene Glycol ◽  
High Weight ◽  
Low Molecular Weight ◽  
Poly Ethylene Glycol ◽  
Degradation Rates ◽  
Degradation Behaviors ◽  
The Mean ◽  
Poly Ethylene ◽  
Lower Glass Transition Temperature

In this work, microporous membrane biomaterials based on high weight molecular polylactide (PLA) and low molecular weight poly(ethylene glycol) (PEG) using rapid solvent evaporation method were prepared and investigated. The effect of PEG segments added on the thermal and degradation behaviors was studied. According to the results, produced PLA/PEG biomaterial has lower glass transition temperature (Tg)in comparison with neat PLA. It was also found that the degradation rates of the PLA/PEG biomaterials were significantly increased with adding of PEG, which explained by increasing hydrophilic groups. For better porous fixation, CL-blocked polyisocyanate (CL-bp), which was synthesized from reaction of isophorone diisocyanate (IPDI) with dimethylol propionic acid (DMPA) and Trimethylolpropane (TMP) followed by addition of caprolactam (CL), were introduced. The microporous forms were observed by the scanning electron microscope (SEM), which showed the mean diameters of prepared PLA/PEG microporous were around 10μm.

Simultaneous Isolation of Wheat High Molecular Weight and Low Molecular Weight Glutenin Subunits

1998 ◽  
Vol 28 (1) ◽  
pp. 25-32 ◽  
Author(s):  
I.M. Verbruggen ◽  
W.S. Veraverbeke ◽  
A. Vandamme ◽  
J.A. Delcour
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Low Molecular Weight ◽  
Glutenin Subunits

scholarly journals The interrelations between high- and low-molecular-weight forms of normal and mutant (Krabbe-disease) galactocerebrosidase

1980 ◽  
Vol 189 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Yoav Ben-Yoseph ◽  
Melinda Hungerford ◽  
Henry L. Nadler
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Specific Activity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Active Form ◽  
Sodium Dodecyl ◽  
Krabbe Disease ◽  
Low Molecular Weight ◽  
Molecular Weight Form

Galactocerebrosidase (β-d-galactosyl-N-acylsphingosine galactohydrolase; EC 3.2.1.46) activity of brain and liver preparations from normal individuals and patients with Krabbe disease (globoid-cell leukodystrophy) have been separated by gel filtration into four different molecular-weight forms. The apparent mol.wts. were 760000±34000 and 121000±10000 for the high- and low-molecular-weight forms (peaks I and IV respectively) and 499000±22000 (mean±s.d.) and 256000±12000 for the intermediate forms (peaks II and III respectively). On examination by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, the high- and low-molecular-weight forms revealed a single protein band with a similar mobility corresponding to a mol.wt. of about 125000. Antigenic identity was demonstrated between the various molecular-weight forms of the normal and the mutant galactocerebrosidases by using antisera against either the high- or the low-molecular-weight enzymes. The high-molecular-weight form of galactocerebrosidase was found to possess higher specific activity toward natural substrates when compared with the low-molecular-weight form. It is suggested that the high-molecular-weight enzyme is the active form in vivo and an aggregation process that proceeds from a monomer (mol.wt. approx. 125000) to a dimer (mol.wt. approx. 250000) and from the dimer to either a tetramer (mol.wt. approx. 500000) or a hexamer (mol.wt. approx. 750000) takes place in normal as well as in Krabbe-disease tissues.

Sign in / Sign up

Export Citation Format

Share Document