High Molecular Weight Acid Research Articles

The Catalytic Effect of Low Molecular Weight Acids on the Physicochemical and Dielectric Properties of Oil-Paper Insulation Systems.

In most industrialized countries, power transformers built several decades ago are approaching the end of their operational lifespan. The ongoing energy transition, focused on developing 100% renewable energy sources and accelerating global transportation electrification, further exacerbates these assets. Combined with rising electricity demand, there is an increasing risk of critical transformers' degradation acceleration. In this context, understanding the aging mechanisms of the insulation system inside these essential assets, which form the core of every energy network, becomes paramount for today's managers and engineers responsible for their operations. The acids generated through oil oxidation can be classified into two categories: low molecular weight acids (LMAs), which are inherently more hydrophilic and consequently have a greater impact on the degradation rate of solid insulation through hydrolysis, and high molecular weight acids (HMAs), which do not significantly contribute to the degradation of paper insulation. This study specifically addresses the impact of acids generated through oil oxidation-focusing on LMAs. New oil samples were infused with different ratios of LMAs before impregnation. The impregnated paper samples underwent thermal aging at 115 °C. Different physicochemical and dielectric properties were investigated. The investigations revealed that oils blended with formic acid exhibited more adverse effects on the insulation system compared to other LMAs. This information is essential for industry professionals seeking to mitigate the risks associated with transformer degradation and extend the lifespan of these critical assets during the energy transition.

Loss-of-Life Analyses Based on Modified Arrhenius and Relative Aging Rate for Non-Thermally Upgraded Paper in Oil-Immersed Transformer

This study evaluates the Loss-of-Life (LOL) based on the modified relative aging rate of an Oil Natural Air Natural (ONAN) transformer with voltage and power ratings of 132/33 kV and 60 MVA. The study’s methodology included the determination of the Hotspot Temperature (HST) based on the differential equation in IEC 60076-7. The loading and ambient temperature profiles for HST determination are forecasted based on the Seasonal Autoregressive Integrated Moving Average (SARIMA). Next, a new relative aging rate was developed based on the Arrhenius equation, considering the pre-exponential factors governed by oxygen, moisture in paper, and acids at different content levels. The LOL was computed based on the new relative aging rate. The study’s main aim is to examine the impact of pre-exponential factors on the LOL based on modified Arrhenius and relative aging rate. The results indicate that the LOLs for different conditions increase as the oxygen, moisture, low molecular weight acid (LMA), and high molecular weight acid (HMA) increase. The LOLs are 46 days, 1,354 days, and 2,662 days in the presence of 12,000 ppm, 21,000 ppm, and 30,000 ppm of oxygen. In 1%, 3%, and 5% moisture, the LOLs are 477 days, 2,799 days, and 7,315 days. At 1% moisture, the LOL is 1,418 days for LMA, while for HMA, it is 122 days. The LMA has the highest impact on the LOL compared to other aging acceleration factors.

Low molecular weight acids and OATP1B mediated hepatic clearance: In vitro and in vivo evaluation using novel hypoxia-inducible factor prolyl hydroxylase inhibitors (Dustats).

Organic anion transporting polypeptide (OATP1B) plays a key role in the hepatic clearance of a majority of high molecular weight (MW) acids and zwitterions. Here, we evaluated the role of OATP1B-mediated uptake in the clearance of novel hypoxia-inducible factor prolyl hydroxylase inhibitors ("Dustats"), which are typically low MW (300-400 daltons) aliphatic carboxylic acids. Five acid dustats, namely daprodustat, desidustat, enarodustat, roxadustat and vadadustat, showed specific transport by OATP1B1/1B3 in transporter-transfected HEK293 cells. Neutral compound, molidustat, was not a substrate to OATP1B1/1B3. None of the dustats showed transport by other hepatic uptake transporters, including NTCP, OAT2 and OAT7. In the primary human hepatocytes, uptake of all acids was significantly reduced by rifampin (OATP1B inhibitor); with an estimated fraction transported by OATP1B (ft ,OATP1B) of up to >80% (daprodustat). Molidustat uptake was minimally inhibited by rifampin; and low permeability acids (desidustat and enarodustat) also showed biliary efflux in sandwich culture human hepatocytes. In vivo, intravenous pharmacokinetics of all 5 acids was significantly altered by a single-dose rifampin (30 mg/kg) in Cynomolgus monkey. Hepatic clearance (non-renal) was about 4-fold (vadadustat) to >11-fod (daprodustat and roxadustat) higher in control group compared to rifampin-treated subjects. In vivo ft ,OATP1B was estimated to be ~70-90%. In the case of molidustat, rifampin had a minimal effect on overall clearance. Rifampin also considerably reduced volume of distribution of daprodustat and roxadustat. Overall, OATP1B significantly contribute to the hepatic clearance and pharmacokinetics of several dustats, which are low MW carboxylic acids. OATP1B activity should therefore by evaluated in this property space. Significance Statement Our in vitro and in vivo results suggest that OATP1B-mediated hepatic uptake play a significant role in the pharmacokinetics of low MW acidic dustats, which are being developed or approved for the treatment of anemia in chronic kidney disease. Significant active uptake mechanisms are not apparent for the neutral compound, molidustat. Characterization of uptake mechanisms is therefore important in predicting human pharmacokinetics and evaluating drug-drug interactions for low MW acids.

Применение хромато-масс спектрометрии для определения кислотного состава трансформаторного масла

This article presents the results of a study of the acid composition of transformer oil from high-voltage transformers that have been in operation for more than 30 years. The acid composition of oils is studied using a new technique based on a highly sensitive and highly selective analysis method — chromato-mass spectrometry. The technique makes it possible to determine the acid composition of the insulating oil in the context of low molecular weight acids (LMA), high molecular weight acids (HMA) and phenolic compounds (PC). The structure of some compounds identified in oil is given. It has been established that during oil aging, among the acid compounds, the following are predominantly formed: HMA (60–95 %) > PC (3–16 %) > LMA (1–6 %). As part of the research, it is found that the share of the most dangerous low molecular weight acids in the total amount of acidic compounds is no more than 12 %. The rest of the acidity of the oil is due to the presence of macromolecular and phenolic compounds, which do not adversely affect the insulating properties of oil and paper in the detected concentrations, and some of them (compounds of a phenolic nature), on the contrary, even improve the stability against oxidation. These extended tests of oil samples from operating high-voltage equipment are of practical value in preventive diagnostics of the condition of its insulation.

Adding Krill Oil and Low Molecular Weight Hyaluronic Acid to Movoflex® Soft Chews Helps Improve Dogs’ Mobility

Movoflex® Soft Chew (Virbac, USA) is a nutritional supplement to support dogs’ mobility. It contains a unique combination of five ingredients: eggshell membrane, hyaluronic acid (HA) of high molecular weight, Boswellia serrata extract, astaxanthin, and vitamin D3. Krill oil and low molecular weight HA are now added to the supplement. The tolerance of this advanced formula was first evaluated in dogs. The aspect, palatability of the chew, and effectiveness on mobility criteria were then assessed by sixty-nine dog owners who were regular users of the current Movoflex® Soft Chews. The chew was found to be well-tolerated and similar in terms of aspect and acceptability to the current one. All but one mobility criteria significantly improved after 30 days, including the ability to walk, climb, stand, interact with people, or the way of walking.

Paper Lifetime Mathematical Modelling based on Multi Pre-Exponential Factors for Oil-Immersed Transformer

This work examines the impact of multi pre-exponential factors on the lifetime modelling of the paper in oil-immersed transformers. First, the corresponding pre-exponential factor was determined based on the concentrations of the three parameters known as oxygen, moisture and acid. Next, the pre-exponential factor for each of the parameters at different concentrations was combined based on the summative approach to obtain the overall impact on the lifetime of the paper. It is found that the expected life of the paper for overall multi pre-exponential factors is higher than either single or double pre-exponential factors. For a single pre-exponential factor, the expected life of the paper decreases by a factor of 59.8 as the oxygen concentration increases from 15,000 ppm to 210,000 ppm. Moisture can decrease the expected life of the paper by a factor of 34 as it increases from 0.5% to 5%. Low molecular weight acid (LMA) has a higher impact than high molecular weight acid (HMA), whereby its impact is further enhanced through multi pre-exponential factor effect whereby the expected life of the paper decreases by a factor of 7.9 as the moisture content increases from 0.5% to 5% and oxygen increases from 300 ppm to 20,000 ppm.

Multidisciplinary team in temporomandibular disorders

Introduction The temporomandibular disorders (TMD) are one of the main concerns regarding orofacial pathologies and there are an ascending number of cases. They are characterised as a group of pathological conditions that may affect the temporomandibular joint (TMJ), the masticatory musculature and/or other adjacent anatomical structures, leading to pain and dysfunction [1]. The multifactorial aetiology of TMD affects a relatively large number of the world population and requires a multidisciplinary evaluation and diagnosis by the clinical team [2]. Among the various elements that constitute the multidisciplinary team we highlight the dentist and the physiotherapist. The dentist as a first-line professional, most of the time is responsible for the identification of patients potentially at risk and for the follow-up of those who already present the disease [3]. On the other hand, the physiotherapist aims to reduce musculoskeletal pain, promote muscle relaxation, reduce muscle hyperactivity, improve function by restoring the quality and quantity of mandibular movements and maximise joint mobility [4]. Description of the clinical case A 24-year-old female patient with a history of temporomandibular disorder and bruxism she presented an non-assisted mouth opening (UMO) of 28 mm and an assisted mouth opening with pain in the masseter and TMJ bilaterally of 29 mm, after the clinical assessment with the DC/TMD protocol we arrived at a diagnosis of disc displacement without reduction (DDwR) with limited opening, degenerative joint disease in the left TMJ, arthralgia (II), myofascial pain (III) in the masseter with pain referred to other anatomical regions. All the assumptions of the Helsinki Declaration have been fulfilled and an informed consent for clinical case of Clinica Dentária Egas Moniz approved by the ethic commission of Instituto Universitário Egas Moniz. The treatment plan consisted of cognitive behavioural therapy (CBT), prescription of muscle relaxants, occlusal splint especially for reduction of overload due to bruxism, infiltration with 1 ml of hyaluronic acid of high molecular weight in the TMJ bilaterally followed by articular mobilisation techniques and neuromuscular and myofascial techniques. The patient was instructed to continue with the physiotherapy. Results The follow up was made 2 months after with 8 sessions of physiotherapy and 1 more hyaluronic acid infiltration bilaterally as protocoled session, we could observe an absence of temporomandibular joint pain, UMO of 42 mm, decreased crepitation, decreased intensity of myofascial pain (I) and (DDwR) without limited opening. Discussion and conclusion The multidisciplinary dentist-physiotherapist team combines inputs from different professions with the aim of promoting the best patient care and represents an added value for the management of the signs/symptoms of patients with temporomandibular dysfunction.

Diffusion of nanoparticles within a semidilute polyelectrolyte solution.

We studied the diffusion of charged gold nanoparticles within a semidilute solution of weakly charged polyelectrolyte, polyacrylic acid (PAA) of high molecular weight (Mw = 106 g mol-1) by using fluorescence correlation spectroscopy (FCS). Nanoparticle size (d) was varied between 5 nm to 40 nm and PAA volume fraction (φ) in water ranged from about 8φ* to 33φ*, where φ* is the overlap volume fraction. The reduced diffusion coefficient - defined as -D/Do, where D is the diffusion coefficient in PAA solution and Do is that in neat water - has a weak dependence on the particle size. D follows a power law of the form ∼φ-0.5, which can be explained by a mean-field hydrodynamic theory in porous medium. Additional, rheology measurements showed a zero shear rate viscosity and shear thinning, which are typical of high molecular weight polyelectrolytes.

Decomposition of volatile fatty acids using electron beam irradiation

Volatile fatty acids (VFAs) are representative odorous compounds. This study was carried out to decompose VFAs using electron beam irradiation. Acetic acid, propionic acid, butyric acid, isovaleric acid, and valeric acid were used as target VFAs. In order to confirm the decomposition efficiency and characteristics by various influential factors, experiments on the absorbed dose, background gas, and initial concentration were performed. The results confirmed that the removal efficiency increased with an increase of the absorbed dose. In addition, the removal efficiency was increased with an increase of the molecular weight of these compounds (in the following order: acetic acid < propionic acid < butyric acid < isovaleric acid < valeric acid). The removal efficiencies of all target VFAs were highest when used with O2 as a background gas. We found the lowest removal efficiency at the He atmosphere. The results of by-product analysis confirmed that valeric acid was decomposed into butyric acid and propionic acid, and then decomposed into acetic acid. That is, high molecular weight acids would be decomposed into low molecular weight acids by electron beam irradiation.

Intra-articular viscosupplementation of hyaluronic acids in an experimental osteoarthritis model

ObjectiveTo analyze, from the immunohistochemical perspective, the effects of hyaluronic acid of different molecular weights in an experimental model of osteoarthritis in rabbits. MethodsForty-four male California rabbits were randomly assigned to three different groups (PR, S, and P) and submitted to the resection of the anterior cruciate ligament of the right knee. Three weeks after the surgical procedure, three intra-articular weekly injections were carried out with low-molecular-weight native hyaluronic acid (Hyalgan®) to PR group, high molecular weight branched chain hyaluronic acid (Synvisc®) to group S, and saline solution 0.9% to group P. All animals were sacrificed 12 weeks after the surgical procedure, and the tibial plateaus of the infiltrated knees were then dissected. Histological sections of cartilage from the tibial plateau support areas were stained with immunohistochemical markers in order to investigate the amount of metalloproteases (MMPs 3 and 13) and their inhibitors (TIMPs 1 and 3). The staining intensity was quantified on a Zeiss Imager.Z2 Metasystems microscope and analyzed by Metafer4 Msearch software. ResultsThe chondroprotective effect of the hyaluronic acids used in the study was demonstrated when compared to the control group. However, the comparison between them presented no significant statistical difference regarding chondroprotection. ConclusionThe injection of saline solution demonstrated signs of OA development, while adding native hyaluronic acid of low molecular weight (Hyalgan®) and hyaluronic acid of high molecular weight (Synvisc®) protected the articular cartilage in this model of OA.

Extracellular nucleic acids of the marine bacterium Rhodovulum sulfidophilum and recombinant RNA production technology using bacteria.

Extracellular nucleic acids of high molecular weight are detected ubiquitously in seawater. Recent studies have indicated that these nucleic acids are, at least in part, derived from active production by some bacteria. The marine bacterium Rhodovulum sulfidophilum is one of those bacteria. Rhodovulumsulfidophilum is a non-sulfur phototrophic marine bacterium that is known to form structured communities of cells called flocs, and to produce extracellular nucleic acids in culture media. Recently, it has been revealed that this bacterium produces gene transfer agent-like particles and that this particle production may be related to the extracellular nucleic acid production mechanism. This review provides a summary of recent physiological and genetic studies of these phenomena and also introduces a new method for extracellular production of artificial and biologically functional RNAs using this bacterium. In addition, artificial RNA production using Escherichia coli, which is related to this topic, will also be described.

Viscossuplementação intra‐articular de ácidos hialurônicos em modelo experimental de osteoartrite

ObjectiveTo analyze, from the immunohistochemical perspective, the effects of hyaluronic acid of different molecular weights in an experimental model of osteoarthritis in rabbits. MethodsForty‐four male California rabbits were randomly assigned to three different groups (PR, S, and P) and submitted to the resection of the anterior cruciate ligament of the right knee. Three weeks after the surgical procedure, three intra‐articular weekly injections were carried out with low‐molecular‐weight native hyaluronic acid (Hyalgan®) to PR group, high molecular weight branched chain hyaluronic acid (Synvisc®) to group S, and saline solution 0.9% to group P. All animals were sacrificed 12 weeks after the surgical procedure, and the tibial plateaus of the infiltrated knees were then dissected. Histological sections of cartilage from the tibial plateau support areas were stained with immunohistochemical markers in order to investigate the amount of metalloproteases (MMPs 3 and 13) and their inhibitors (TIMPs 1 and 3). The staining intensity was quantified on a Zeiss Imager.Z2 Metasystems microscope and analyzed by Metafer4 Msearch software. ResultsThe chondroprotective effect of the hyaluronic acids used in the study was demonstrated when compared to the control group. However, the comparison between them presented no significant statistical difference regarding chondroprotection. ConclusionThe injection of saline solution demonstrated signs of OA development, while adding native hyaluronic acid of low molecular weight (Hyalgan®) and hyaluronic acid of high molecular weight (Synvisc®) protected the articular cartilage in this model of OA.

Fate of terrigenous organic matter across the Laptev Sea from the mouth of the Lena River to the deep sea of the Arctic interior

Abstract. Ongoing global warming in high latitudes may cause an increasing supply of permafrost-derived organic carbon through both river discharge and coastal erosion to the Arctic shelves. Mobilized permafrost carbon can be either buried in sediments, transported to the deep sea or degraded to CO2 and outgassed, potentially constituting a positive feedback to climate change. This study aims to assess the fate of terrigenous organic carbon (TerrOC) in the Arctic marine environment by exploring how it changes in concentration, composition and degradation status across the wide Laptev Sea shelf. We analyzed a suite of terrestrial biomarkers as well as source-diagnostic bulk carbon isotopes (δ13C, Δ14C) in surface sediments from a Laptev Sea transect spanning more than 800 km from the Lena River mouth (&lt; 10 m water depth) across the shelf to the slope and rise (2000–3000 m water depth). These data provide a broad view on different TerrOC pools and their behavior during cross-shelf transport. The concentrations of lignin phenols, cutin acids and high-molecular-weight (HMW) wax lipids (tracers of vascular plants) decrease by 89–99 % along the transect. Molecular-based degradation proxies for TerrOC (e.g., the carbon preference index of HMW lipids, the HMW acids ∕ alkanes ratio and the acid ∕ aldehyde ratio of lignin phenols) display a trend to more degraded TerrOC with increasing distance from the coast. We infer that the degree of degradation of permafrost-derived TerrOC is a function of the time spent under oxic conditions during protracted cross-shelf transport. Future work should therefore seek to constrain cross-shelf transport times in order to compute a TerrOC degradation rate and thereby help to quantify potential carbon–climate feedbacks.

Ageing assessment of transformer paper insulation through post mortem analysis

A post mortem analysis of scrapped transformers provides an opportunity to directly measure the properties of in-service aged paper insulation. Investigations on 10 scrapped 275 kV and 400 kV power transformers were carried out, where Tensile Index (TI) and Low Molecular Weight Acid (LMA) of the paper insulation sampled from various locations were measured. Multiple-layer TI profile demonstrated the effect of oxidized oil on paper ageing which was confirmed by laboratory ageing experiments. It is LMA rather than High Molecular Weight Acid (HMA) that accelerates the paper degradation. LMA acts as the paper ageing accelerator and also as the paper degradation by-product, supporting the view that self-accelerated hydrolysis process is the main paper ageing mechanism. Finally, a generic relationship between LMA in paper and TI of paper was revealed based on both in-service and laboratory ageing data, i.e. the lower the TI of paper, the higher value of LMA in paper is measured. It implies that LMA in oil can be a potential paper ageing indicator pro viding a link between LMA in oil and paper is found.

Chemical properties of the oil from Pistacia khinjuk fruits growing wild in Iran

17.82, 17.44, 5.73, 2.31, and 1.5%, respectively 2. A study of the chemical properties of the oil from the P. khinjuk fruits has not been done previously. Therefore, this study was undertaken to investigate the chemical properties of the oil from P. khinjuk fruits (PKF) grown in Iran and to compare its properties with those of P. vera L. cv. Ohadi kernel (PVOK) oil (the most plentiful cultivar of P. vera in Iran) used as the control. The chemical composition and characteristics of the PKF and PVOK oils are shown in Table 1. The percentage of saturated fatty acids (SFA) of the PKF oil (20.76%) was significantly higher than that of the PVOK (9.81%) oil. Among the monounsaturated fatty acid (MUFA), the percentage of palmitoleic acid (C16:1) in the PKF oil (5.94%) was about 6.6 times higher than that of the PVOK (0.98%) oil. There was no statistically signicant difference between the percentages of oleic acid of the two oils studied (51.91–52.05). The polyunsaturated fatty acids (PUFA) content of the PVOK oil (37.06%) was significantly greater than that of the PKF oil (19.52%). From the information stated above, the PKF oil showed a ratio of unsaturated and saturated fatty acids (USFA/SFA) (3.81) and a Cox value (2.66) that were lower than those of PVOK (9.18 and 4.46, respectively) oil, which makes it particularly resistant to oxidation. The PV of the PKF oil (1.99 meq per kg oil) was significantly greater than that of the PVOK oil (0.25 meq per kg oil) (Table 1). This indicates that the PKF oils were oxidized more than the PVOK oil. This might be due to its improper storage and handling conditions as compared with the PVOK oil. The IV, which is considered as a measure of oil unsaturation for the PKF and PVOK oils, was 85.15 and 110.78, respectively. The difference in IVs among the PKF and PVOK oils was due to their different fatty acid composition. The PKF oil has a greater SFA content (C16:0 and C18:0) and a lower PUFA content (mainly, C18:2) than those of PVOK oil. As shown in Table 1, the SN of the PKF oil (79.46) was significantly lower than that of the PVOK oil (125.71) and also much lower than that of common vegetable oils with an average SN range of 175–250. Because there is an inverse relationship between SN and weight of fatty acids in the oil, it can be inferred that the PKF oil contains a great number of fatty acids of high molecular weight 3. However, as can be seen in Table 1, the fatty acid composition of the oils studied cannot be the only reason for the considerable differences in their average molecular weight. In fact, their different wax and USM contents constitute the main contribution of these differences 4.

AB0991 Efficiency of the intraarticular application of hyaluronic acid in the treatment of secondary osteoarthritis of the knee in patients with rheumatoid arthritis and in patients with primary osteoarthritis

BackgroundThe use of hyaluronic acid in the form of intraarticular injections in the treatment of the patients with primary osteoarthritis (OA) of the knee leads to a rapid and time-limited...

AB0600 Efficacy of intraarticular application of hyaluronate in comparison to intraarticular application of betamethasone in the treatment of primary osteoarthritis of the knee

BackgroundApplication of intraarticular injections of hyaluronic acid (hyaluronate sodium) and betamethasone (a two-component glucocorticoid with rapid and delayed action) is one of the widely accepted treatments of primary osteoarthritis (POA).ObjectivesTo...

Preparation and characterization of high‐molecular‐weight poly(l‐lactic acid) by chain‐extending reaction with phosphites

AbstractPoly(l‐lactic acid) (PLLA) of high molecular weight was prepared by a chain‐extending reaction in a microcompounder. Phosphites were used as chain extenders to increase the molecular weight of the PLLA prepolymer, which was prepared by the bulk polycondensation of l‐lactic acid. The effects of the amount of phosphite, the temperature, and the screw speed on the torque of the PLLA melt were studied. Under the optimal conditions, the molecular weight of PLLA increased from 62,100 to 126,000 g/mol. The chemical structure and crystallinity of PLLA were characterized by Fourier transform infrared spectroscopy, 1H‐NMR and 13C‐NMR, differential scanning calorimetry, and X‐ray diffraction. The mechanical properties of PLLA were measured. The results indicate that triphenyl phosphite (TPPi) was an effective chain extender for PLLA. The role of the TPPi in chain extending is suggested to be an esterification‐promotion agent. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

Effects of D-003 on lipopolysaccharides-induced osteonecrosis in rabbits

D-003, a mixture of high molecular weight acids, inhibits cholesterol synthesis prior to mevalonate and prevents osteoporosis induced by ovariectomy in rats, and both osteoporosis and osteonecrosis induced by corticoids in rats. The aim of this study was to investigate effects of D-003 on lipopolysaccharides-induced osteonecrosis in rabbits. Animals were randomized into 5 groups: a sham and four groups injected with lipopolysaccharides: one treated orally with vehicle and three with D-003 (5, 25 and 200 mg/kg, respectively) during four weeks. We assessed the effects of treatments on the incidence of osteonecrosis (number of animals with osteonecrosis lesions/animals per group), the mean numbers and areas of osteonecrosis per animal and on the mean sizes of the bone marrow fat cells. The incidence of osteonecrosis in the groups of D-003 25 and 200 mg/kg was significantly lower than in the positive controls. The reduction of osteonecrosis increased with the doses, but significant dose-dependence relationship was not achieved. D-003 significantly and dose-dependently decreased the number of osteonecrosis lesions per animal as compared to the positive controls. Likewise, the mean osteonecrosis areas in the proximal femoral and humeral bones were significantly decreased by D-003. The injection of lipopolysaccharides significantly increased the average size of bone marrow fat cells as compared to the negative controls, and such increase was significantly and markedly reduced with D-003. It is concluded that D-003 reduced the incidence, number and percent areas of osteonecrosis lesions, and the size of bone marrow fat cells, a marker of adipogenesis, in rabbits with lipopolysaccharides-induced ostenonecrosis.

ADSORPTION OF TANNIC ACID BY HYPER-CROSSLINKED RESIN MODIFIED BY AMINO FUNCTION GROUPS

Tannic acid(TA) as a typical natural organic acid of high solubility and medium molecular weight,was used to study the adsorption act and mechanism on a new hyper-crosslinked resin modified by amino function groups WJN-08.The adsorption isotherm data indicates that the equllibrium adsorption capacity of WJN-08 for TA is 15% higher than that of other commercial adsorbents.Moreover,the static adsorption assay indicates that the adsorption capacity for TA is related to the pore structure and the amounts of amino function groups of resin.The FTIR spectra of WJN-08 before and after adsorption of TA indicate that both "π-π" conjugation and electric attraction are the adsorption force during the adsorption process.The adsorption enthalpy changes ΔH of TA by WJN-08 is in a range from 20 to 22 kJ mol~(-1),which exhibit the adsorption is a chemical and endothermic process.Batch kinetic studies indicate that the adsorption of TA on WJN-08 can be fitted by the membrane and intra-particle diffusion model.In particular,excellent adsorption and de-sorption performance of WJN-08 for TA is shown in dynamic column assay.The break though adsorption capacity is 19.56 mg g~(-1) and saturation adsorption capacity is 22.43 mg g~(-1),respectivey,and the desorption rate of TA on WJN-08 is more than 98%.