The flotation separation of chalcopyrite from monoclinic pyrrhotite using food-grade guar gum(FGG) as a depressant was studied through flotation tests, kinetic studies, dynamic potential measurements, adsorption exper...The flotation separation of chalcopyrite from monoclinic pyrrhotite using food-grade guar gum(FGG) as a depressant was studied through flotation tests, kinetic studies, dynamic potential measurements, adsorption experiments, and infrared spectral analyses. The microflotation results showed that the flotation separation of chalcopyrite from monoclinic pyrrhotite could not be realized by adding mixed aerofloat(CSU11) alone. The depressant FGG exhibited a selective depression effect on monoclinic pyrrhotite by controlling the pulp pH range from 5.0 to 6.0, with a maximum floatability variation of 79.36% in the presence of CSU11. The flotation kinetics, zeta-potential, adsorption, and infrared spectroscopy studies revealed that the FGG could absorb more strongly on the surface of monoclinic pyrrhotite than on the surface of chalcopyrite. In addition, the results revealed that the interaction of FGG with the monoclinic pyrrhotite surface was governed primarily by strong chemisorption, whereas FGG mainly bonded to chalcopyrite through hydrogen bonding. This difference was responsible for the excellent depression selectivity of FGG toward monoclinic pyrrhotite flotation and weak depression effect toward chalcopyrite flotation.展开更多
The depression behavior and mechanism of guar gum on talc-type scheelite flotation were systematically investigated by flotation experiments, adsorption tests, zeta-potential measurements, and infrared spectroscopic a...The depression behavior and mechanism of guar gum on talc-type scheelite flotation were systematically investigated by flotation experiments, adsorption tests, zeta-potential measurements, and infrared spectroscopic analyses. The flotation results for monominerals, mixed minerals, and actual mineral samples indicated that guar gum exhibited much higher selective depression for talc than for scheelite. Bench-scale closed-circuit tests showed that a tungsten concentrate with a WO_3 grade of 51.43% and a WO_3 recovery of 76.18% was obtained. Adsorption tests, zeta-potential measurements, and infrared spectral analyses confirmed that guar gum absorbed more strongly onto the talc surface than onto the scheelite surface because of chemisorption between guar gum and talc. This chemisorption is responsible for the guar gum's highly selective depression for talc and small depression for scheelite. The flotation results provide technical support for talc-type scheelite flotation.展开更多
AIM:To assess the effects of partially hydrolyzed guar gum(PHGG) diet supplement in pediatric chronic abdominal pain(CAP) and irritable bowel syndrome(IBS).METHODS:A randomized,double-blind pilot study was performed i...AIM:To assess the effects of partially hydrolyzed guar gum(PHGG) diet supplement in pediatric chronic abdominal pain(CAP) and irritable bowel syndrome(IBS).METHODS:A randomized,double-blind pilot study was performed in sixty children(8-16 years) with functional bowel disorders,such as CAP or IBS,diagnosed according to Rome Ⅲ criteria.All patients underwent ultrasound,blood and stool examinations to rule out any organic disease.Patients were allocated to receive PHGG at dosage of 5 g/d(n = 30) or placebo(fruitjuice n = 30) for 4 wk.The evaluation of the efficacy of fiber supplement included IBS symptom severity score(Birmingham IBS Questionnaire),severity of abdominal pain(Wong-Baker Face Pain Rating Score) and bowel habit(Bristol Stool Scale).Symptom scores were completed at 2,4,and 8 wk.The change from baseline in the symptom severity scale at the end of treatment and at 4 wk follow-up after treatment was the primary endpoint.The secondary endpoint was to evaluate compliance to supplementation with the PHGG in the pediatric population.Differences within groups during the treatment period and follow-up were evaluated by the Wilcoxon signed-rank test.RESULTS:The results of the study were assessed considering some variables,such as frequency and intensity of symptoms with modifications of the bowel habit.Both groups were balanced for baseline characteristics and all patients completed the study.Group A(PHGG group) presented a higher level of efficacy compared to group B(control group),(43% vs 5%,P = 0.025) in reducing clinical symptoms with modification of Birmingham IBS score(median 0 ± 1 vs 4 ± 1,P = 0.025),in intensity of CAP assessed with the Wong-Baker Face Pain Rating Score and in normalization of bowel habit evaluated with the Bristol Stool Scale(40% vs 13.3%,P = 0.025).In IBS subgroups,statistical analysis shown a tendency toward normalization of bowel movements,but there was no difference in the prevalence of improvement in two bowel habit subsets.PHGG was therefore better tolerated without any adverse effects.CONCLUSION:Although the cause of pediatric functional gastrointestinal disorders is not known,the results show that complementary therapy with PHGG may have beneficial effects on symptom control.展开更多
This paper reports the systematic investigation on the flocculation,sedimentation and consolidation characteristics of kaolinite using guar gum as a green flocculant.In-situ flocculation behavior of kaolinite at vario...This paper reports the systematic investigation on the flocculation,sedimentation and consolidation characteristics of kaolinite using guar gum as a green flocculant.In-situ flocculation behavior of kaolinite at various pH,guar gum dosages,and ionic strength were studied using a light scattering technique.The effect of these parameters on the settling rate,solid consolidation,and supernatant liquid clarity was recorded.The morphology of kaolinite and flocculated kaolinite aggregates were analyzed using FESEM.The morphology studies suggest that it is poorly crystalline with multiple steps on edge,broken edge;laminar with high aspect ratio and have rough basal surface.The complex irregularity on the basal surface and the presence of multiple steps in the edges,broken edges(hydroxyl groups)have facilitated the guar gum adsorption.The isoelectric point of kaolinite is pH 3.96.The pH,ionic strength and flocculant dosage have a significant effect on the kaolinite settling rate.The guar gum has exhibited excellent turbidity removal efficiency at pH 5.The turbidity removal is inefficient at pH 10.However,guar gum has shown high turbidity removal with 80%transmission at pH 10 in the presence of a KNO3 electrolyte.展开更多
Nowadays,using biopolymer as a ground improvement method has become very popular.However,since biopolymers are organic and degradable,their long-term effect is not fully known.In this study,the effects of biopolymers ...Nowadays,using biopolymer as a ground improvement method has become very popular.However,since biopolymers are organic and degradable,their long-term effect is not fully known.In this study,the effects of biopolymers on the mechanical behavior of kaolin clay were investigated through a comprehensive program of experiments.Two types of biopolymer,i.e.xanthan gum and guar gum were chosen to investigate the effect of biopolymer type.For this purpose,specimens were prepared using standard Proctor energy at four different water contents(25%,30%35%and 40%)with 0.5%,1%,1.5%and 2%biopolymer inclusions.The specimens were cured for 1 d,7 d,28 d and 90 d.Moreover,some of the specimens were kept in the curing room for 3 years to observe the long-term effect of the biopolymers.At the end of the curing periods,the specimens were subjected to unconfined compression test,and scanning electron microscopy(SEM)analysis was performed to observe the mechanism of strength improvement.The results revealed that the unconfined compressive strength(UCS)of the specimens treated with biopolymers increased in all biopolymer inclusion levels and water contents up to a 90-d curing period.For specimens containing xanthan gum,the maximum strength increase was observed at 25%water content and 2%xanthan gum with 90-d curing.The strength increased 5.23 times induced by xanthan gum addition when compared to the pure clay.Moreover,the increase in strength reached 8.53 times in specimens treated with guar gum.Besides,increasing water content caused more ductile behavior,thus increasing the axial deformation.展开更多
The synergistic interaction between the cationic guar gum (the ammonium hydroxy-propyl-trimethyl chloride of guar gum) and sodium alginate has been studied. The effects of the mass ratio of them, mixed temperature, ba...The synergistic interaction between the cationic guar gum (the ammonium hydroxy-propyl-trimethyl chloride of guar gum) and sodium alginate has been studied. The effects of the mass ratio of them, mixed temperature, balk salt ion concentration, incubation time and pH value on gelation were investigated. It has been observed that there was a gel strength maximum when the mass ratio was 0.6, the mixed temperature was 70°C, the balk salt ion concentration was 1.0 mol·L?1, the incubation time was 30 min and the pH value was 8. Interaction between molecules of these two polysaccharides was investigated by FT-IR spectrometry. Key words cationic guar gum - sodium alginate - gelation - synergism CLC number O 629.12 Foundation item: Supported by the National Natural Science Foundation of China(29574173)Biography: He Dong-bao (1945-), male, Associate professor, research direction: modifying and gelating of natural polysaccharides.展开更多
BACKGROUND The gut-liver axis has attracted much interest in the context of chronic liver disease pathogenesis.Prebiotics such as dietary fibers were shown to attenuate non-alcoholic fatty liver disease(NAFLD)by modul...BACKGROUND The gut-liver axis has attracted much interest in the context of chronic liver disease pathogenesis.Prebiotics such as dietary fibers were shown to attenuate non-alcoholic fatty liver disease(NAFLD)by modulating gut microbiota.Partially hydrolyzed guar gum(PHGG),a water-soluble dietary fiber,has been reported to alleviate the symptoms of various intestinal diseases and metabolic syndromes.However,its effects on NAFLD remain to be fully elucidated.To determine whether treatment with PHGG attenuates NAFLD development in mice through the gut-liver axis.METHODS Seven-week-old male C57BL/6J mice with increased intestinal permeability were fed a control or atherogenic(Ath)diet(a mouse model of NAFLD)for 8 wk,with or without 5%PHGG.Increased intestinal permeability was induced through chronic intermittent administration of low-dose dextran sulfate sodium.Body weight,liver weight,macroscopic findings in the liver,blood biochemistry[aspartate aminotransferase(AST)and alanine aminotransferase(ALT),total cholesterol,triglyceride,free fatty acids,and glucose levels],liver histology,myeloperoxidase activity in liver tissue,mRNA expression in the liver and intestine,serum endotoxin levels in the portal vein,intestinal permeability,and microbiota and short-chain fatty acid(SCFA)profiles in the cecal samples were investigated.RESULTS Mice with increased intestinal permeability subjected to the Ath diet showed significantly increased serum AST and ALT levels,liver fat accumulation,liver inflammatory(tumor necrosis factor-αand monocyte chemotactic protein-1)and fibrogenic(collagen 1a1 andαsmooth muscle actin)marker levels,and liver myeloperoxidase activity,which were significantly attenuated by PHGG treatment.Furthermore,the Ath diet combined with increased intestinal permeability resulted in elevated portal endotoxin levels and activated toll-like receptor(TLR)4 and TLR9 expression,confirming that intestinal permeability was significantly elevated,as observed by evaluating the lumen-to-blood clearance of fluorescein isothiocyanate-conjugated dextran.PHGG treatment did not affect fatty acid metabolism in the liver.However,it decreased lipopolysaccharide signaling through the gut-liver axis.In addition,it significantly increased the abundance of cecal Bacteroides and Clostridium subcluster XIVa.Treatment with PHGG markedly increased the levels of SCFAs,particularly,butyric acid,acetic acid,propionic acid,and formic acid,in the cecal samples.CONCLUSION PHGG partially prevented NAFLD development in mice through the gut-liver axis by modulating microbiota and downstream SCFA profiles.展开更多
HGG (Hydroxypropyl guar gum) was synthesized by phase transfer catalysis for the first time. The effects of alkalinity, phase transfer catalyst, etherification, pH value, temperature, reaction time and stirring spee...HGG (Hydroxypropyl guar gum) was synthesized by phase transfer catalysis for the first time. The effects of alkalinity, phase transfer catalyst, etherification, pH value, temperature, reaction time and stirring speed were investigated. An optimal synthetic reaction technology was established, namely, dose of guar gum is 100 g, propylene oxide 40-50 g, HTAC (hexadecyl trimethyl ammonium chloride ) 1.3-1.7 g, pH value 10-10.5, temperature 45-50℃, and reaction time 3-4 hours. The result shows that the improved HGG has high viscosity. Its dissolution speed, content of insoluble residue, colloid light transparency and stability are apparently superior to guar flour.展开更多
As water-based extraction technologies for producing bitumen from oil sands have received increasing environmental concerns,developing non-aqueous extraction(NAE)technique is of both fundamental and practical importan...As water-based extraction technologies for producing bitumen from oil sands have received increasing environmental concerns,developing non-aqueous extraction(NAE)technique is of both fundamental and practical importance.However,the relatively high concentration of fine solids trapped in the extracted bitumen presents an obstacle for pipeline transport as well as upgrading and refining downstream.This research attempts to provide a solution to fine solids removal without using synthetic additives or affecting bitumen recovery from NAE process.Herein,naturally hydrophilic additives(i.e.,water and high molecular weight guar gum(HGG)produced from Cyamopsiste tragonolobuosr L.Taup.)were introduced to promote the settling of fine solids suspended in bitumen-solvent solution,and the effects of solvents(i.e.,toluene,cyclohexane and their mixtures)were systematically investigated.Aggregate size distribution analyzed by the focused beam reflectance measurements confirmed that the addition of water and HGG could promote the agglomeration and settling of fine solids in all solvents studied.However,the size range and quantity of the agglomerates vary significantly with the solvent's aromatic character.Solvent mixtures demonstrate a superior performance on removing fine solids from bitumen over single solvent.Specifically,in a 3:2 toluene/cyclohexane mixture,the solid content was lowered from 0.66 wt%to 0.09 wt%.展开更多
The reduced viscosity of polymer guar gum solutions containing a certain concentration of sodium dodecyl benzene sulfonate （SDBS） was measured. It has been found that the Huggins coefficient kH of polymer solutions ...The reduced viscosity of polymer guar gum solutions containing a certain concentration of sodium dodecyl benzene sulfonate （SDBS） was measured. It has been found that the Huggins coefficient kH of polymer solutions is very sensitive to the concentration of the surfactant, CSDBS, in solutions. If CSDBS is lower than CMC, the critical micelle concentration of SDBS, kH increases rapidly with CSDBS. On the other hand, if CSDBS is larger than CMC, kH decreases rapidly with CSDBS. Comparatively, the intrinsic viscosity of polymer solution does not show a notable change with CSDBS. The experimental results indicate that the interchain association of polymer guar gum in solution is greatly associated with SDBS interacted with polymer chains through hydrogen bonds. However, the effect of SDBS upon the intrachain association of polymer guar gum solution is negligible, presumably due to the fact that guar gum is a slightly stiffened random-coil chain polymer.展开更多
The tetrahedral borate ion can crosslink with polymer guar gum in aqueous solutions. If the concentration of guar gum is less than 0.045 g/dL, the intramolecular interaction between guar gum and borate ion increases d...The tetrahedral borate ion can crosslink with polymer guar gum in aqueous solutions. If the concentration of guar gum is less than 0.045 g/dL, the intramolecular interaction between guar gum and borate ion increases due to the formation of crosslinks. As a result, the polymer chains of guar gum in solution shrink in size and the reduced viscosity of polymer solution decreases accordingly. On the other hand, if the concentration of guar gum is greater than 0.045 g/dL, the intermolecular interaction becomes apparent due to the same reason. The polymer chains, therefore, associate together and the reduced viscosity of polymer solution increases considerably. According to this technique, the critical concentration c^＊, presented by de-Gennes, is determined successfully.展开更多
Guar [Cyamopsis tetragonoloba （L.） Taub.] is one of the most important industrial crops due to its richness in gum. Understanding the inheritance of gum content is a key to its successful genetic improvement. Gum co...Guar [Cyamopsis tetragonoloba （L.） Taub.] is one of the most important industrial crops due to its richness in gum. Understanding the inheritance of gum content is a key to its successful genetic improvement. Gum content expression is reported to be controlled by additive, dominant, and epistatic effects, and modified by the environment, fg%, a relative gum content calculated by comparing with the gum content of Kinman was used as gum content （%） in this experiment. Reciprocal crosses of two lines of guar, PI 217923 and Lewis, were made to study the heritability of gum content （fg%）. fg% of four plant introductions and four commercial varieties were studied in Lubbock in 1999-2002. Estimates of broadsense heritability （h^2 b,s.） of fg% in Lewis x PI 217923 and PI 217923 x Lewis were 75.53 and 52.74%, respectively. Estimates of narrow-sense heritability （h2 n.s.） of fg% were 40.00 and 29.00% thr Lewis x PI 217923 and PI 217923 x Lewis, respectively. At least one pair of genes were estimated to control the fg% expression in these two crosses, Significant differences of fg% were found among these eight entries. PI 217923 was found to have the highest fg% among the eight entries.展开更多
We prepared, characterized and studied the biodistribution of tamoxifen citrate (TMX) loaded cross-linked guar gum (GG) nanoparticles (NPs). NPs were prepared via a single step emulsion process and particle size evalu...We prepared, characterized and studied the biodistribution of tamoxifen citrate (TMX) loaded cross-linked guar gum (GG) nanoparticles (NPs). NPs were prepared via a single step emulsion process and particle size evaluated. The extent of tissue distribution and retention following oral administration of TMX loaded GG NPs and TMX tablet in female albino mice was analyzed over a period of 48 hours. Till 48 hours, the particles remained detectable in both mammary and ovary tissue (estrogen receptors). Uptake and retention of TMX from NPs and tablet in mammary gland and ovary tissue changed with time. Results showed that the uptake and retention of NPs was more in the mammary gland between 24 - 48 hours (11.2% at 24 h;4.65% at 48 h). As mammary gland is the target organ in breast cancer therapy, it may be concluded that the cross-linked GG NPs are capable of releasing the drug at the target and minimize the uptake and retention in non target tissue, the ovary (7.98% at 24 h;1.9% at 48 h). Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) with time were measured. No abnormal changes in the liver enzymes were observed. GG NPs under study can be used as a drug carrier system for treating cancer.展开更多
Natural gums can be tailored and used for the removal of toxic dyes like crystal violet via grafting techniques. However, grafting via microwave irradiation showed both higher yield and fast reaction kinetics as compa...Natural gums can be tailored and used for the removal of toxic dyes like crystal violet via grafting techniques. However, grafting via microwave irradiation showed both higher yield and fast reaction kinetics as compared to conventional grafting. Silane modified nanoclay has been used to prepare acrylic acid grafted guar gum nanocomposites via microwave irradiation technique. The grafting was confirmed via infrared spectroscopy while XRD diffractograms suggested exfoliation of modified nanoclay in guar gum grafted acrylic acid. The reaction kinetic parameters have been optimized. The effect of nanoclay on swelling characteristics has been examined. The sensitivity of pH on swelling capabilities has also been assessed. The efficiency of the superabsorbent nanocomposite on the absorption of crystal violet dye has been studied. The superabsorbent nanocomposite loaded with 1.75% modified nanocaly was found to be optimal concentration for the removal of crystal violet dye.展开更多
Based on the water quality detection and analysis of guar gum waste liquid,as well as the data of experiments on the treatment of waste liquid under different viscosity and pH conditions,the influencing factors of sol...Based on the water quality detection and analysis of guar gum waste liquid,as well as the data of experiments on the treatment of waste liquid under different viscosity and pH conditions,the influencing factors of solid-liquid separation under conventional"coagulation+filtration"treatment process are studied.Under the conventional"coagulation+filtration"treatment process,the viscosity of guar gum waste liquid is lower than 3 mPa·s;the pH is 6-7.5;the filtration accuracy is not lower than 20μm,which can meet better treatment conditions.This experimental study provides an experimental basis for the optimal design of the treatment process of guar gum waste liquid.展开更多
基金support of the National Key Technology R&D Program of China(No.2015BAB12B02)the Science and Technology Planning Project Guangdong Province,China(No.2013B090800016)
文摘The flotation separation of chalcopyrite from monoclinic pyrrhotite using food-grade guar gum(FGG) as a depressant was studied through flotation tests, kinetic studies, dynamic potential measurements, adsorption experiments, and infrared spectral analyses. The microflotation results showed that the flotation separation of chalcopyrite from monoclinic pyrrhotite could not be realized by adding mixed aerofloat(CSU11) alone. The depressant FGG exhibited a selective depression effect on monoclinic pyrrhotite by controlling the pulp pH range from 5.0 to 6.0, with a maximum floatability variation of 79.36% in the presence of CSU11. The flotation kinetics, zeta-potential, adsorption, and infrared spectroscopy studies revealed that the FGG could absorb more strongly on the surface of monoclinic pyrrhotite than on the surface of chalcopyrite. In addition, the results revealed that the interaction of FGG with the monoclinic pyrrhotite surface was governed primarily by strong chemisorption, whereas FGG mainly bonded to chalcopyrite through hydrogen bonding. This difference was responsible for the excellent depression selectivity of FGG toward monoclinic pyrrhotite flotation and weak depression effect toward chalcopyrite flotation.
基金financially supported by the National Natural Science Foundation of China (No.51404218)the National Key Technology R&D Program (No.2015BAB12B02)the Science and Technology Planning Project of Guangdong Province, China (No.2013B090800016)
文摘The depression behavior and mechanism of guar gum on talc-type scheelite flotation were systematically investigated by flotation experiments, adsorption tests, zeta-potential measurements, and infrared spectroscopic analyses. The flotation results for monominerals, mixed minerals, and actual mineral samples indicated that guar gum exhibited much higher selective depression for talc than for scheelite. Bench-scale closed-circuit tests showed that a tungsten concentrate with a WO_3 grade of 51.43% and a WO_3 recovery of 76.18% was obtained. Adsorption tests, zeta-potential measurements, and infrared spectral analyses confirmed that guar gum absorbed more strongly onto the talc surface than onto the scheelite surface because of chemisorption between guar gum and talc. This chemisorption is responsible for the guar gum's highly selective depression for talc and small depression for scheelite. The flotation results provide technical support for talc-type scheelite flotation.
文摘AIM:To assess the effects of partially hydrolyzed guar gum(PHGG) diet supplement in pediatric chronic abdominal pain(CAP) and irritable bowel syndrome(IBS).METHODS:A randomized,double-blind pilot study was performed in sixty children(8-16 years) with functional bowel disorders,such as CAP or IBS,diagnosed according to Rome Ⅲ criteria.All patients underwent ultrasound,blood and stool examinations to rule out any organic disease.Patients were allocated to receive PHGG at dosage of 5 g/d(n = 30) or placebo(fruitjuice n = 30) for 4 wk.The evaluation of the efficacy of fiber supplement included IBS symptom severity score(Birmingham IBS Questionnaire),severity of abdominal pain(Wong-Baker Face Pain Rating Score) and bowel habit(Bristol Stool Scale).Symptom scores were completed at 2,4,and 8 wk.The change from baseline in the symptom severity scale at the end of treatment and at 4 wk follow-up after treatment was the primary endpoint.The secondary endpoint was to evaluate compliance to supplementation with the PHGG in the pediatric population.Differences within groups during the treatment period and follow-up were evaluated by the Wilcoxon signed-rank test.RESULTS:The results of the study were assessed considering some variables,such as frequency and intensity of symptoms with modifications of the bowel habit.Both groups were balanced for baseline characteristics and all patients completed the study.Group A(PHGG group) presented a higher level of efficacy compared to group B(control group),(43% vs 5%,P = 0.025) in reducing clinical symptoms with modification of Birmingham IBS score(median 0 ± 1 vs 4 ± 1,P = 0.025),in intensity of CAP assessed with the Wong-Baker Face Pain Rating Score and in normalization of bowel habit evaluated with the Bristol Stool Scale(40% vs 13.3%,P = 0.025).In IBS subgroups,statistical analysis shown a tendency toward normalization of bowel movements,but there was no difference in the prevalence of improvement in two bowel habit subsets.PHGG was therefore better tolerated without any adverse effects.CONCLUSION:Although the cause of pediatric functional gastrointestinal disorders is not known,the results show that complementary therapy with PHGG may have beneficial effects on symptom control.
基金support from the Ministry of Steel,Government of India,India(GAP 214).
文摘This paper reports the systematic investigation on the flocculation,sedimentation and consolidation characteristics of kaolinite using guar gum as a green flocculant.In-situ flocculation behavior of kaolinite at various pH,guar gum dosages,and ionic strength were studied using a light scattering technique.The effect of these parameters on the settling rate,solid consolidation,and supernatant liquid clarity was recorded.The morphology of kaolinite and flocculated kaolinite aggregates were analyzed using FESEM.The morphology studies suggest that it is poorly crystalline with multiple steps on edge,broken edge;laminar with high aspect ratio and have rough basal surface.The complex irregularity on the basal surface and the presence of multiple steps in the edges,broken edges(hydroxyl groups)have facilitated the guar gum adsorption.The isoelectric point of kaolinite is pH 3.96.The pH,ionic strength and flocculant dosage have a significant effect on the kaolinite settling rate.The guar gum has exhibited excellent turbidity removal efficiency at pH 5.The turbidity removal is inefficient at pH 10.However,guar gum has shown high turbidity removal with 80%transmission at pH 10 in the presence of a KNO3 electrolyte.
基金the context of the research project“Investigation of strength properties of xanthan treated kaolin clay”(Grant No.16MUH013)funded within Research Projects program of Ege University,Turkey.
文摘Nowadays,using biopolymer as a ground improvement method has become very popular.However,since biopolymers are organic and degradable,their long-term effect is not fully known.In this study,the effects of biopolymers on the mechanical behavior of kaolin clay were investigated through a comprehensive program of experiments.Two types of biopolymer,i.e.xanthan gum and guar gum were chosen to investigate the effect of biopolymer type.For this purpose,specimens were prepared using standard Proctor energy at four different water contents(25%,30%35%and 40%)with 0.5%,1%,1.5%and 2%biopolymer inclusions.The specimens were cured for 1 d,7 d,28 d and 90 d.Moreover,some of the specimens were kept in the curing room for 3 years to observe the long-term effect of the biopolymers.At the end of the curing periods,the specimens were subjected to unconfined compression test,and scanning electron microscopy(SEM)analysis was performed to observe the mechanism of strength improvement.The results revealed that the unconfined compressive strength(UCS)of the specimens treated with biopolymers increased in all biopolymer inclusion levels and water contents up to a 90-d curing period.For specimens containing xanthan gum,the maximum strength increase was observed at 25%water content and 2%xanthan gum with 90-d curing.The strength increased 5.23 times induced by xanthan gum addition when compared to the pure clay.Moreover,the increase in strength reached 8.53 times in specimens treated with guar gum.Besides,increasing water content caused more ductile behavior,thus increasing the axial deformation.
文摘The synergistic interaction between the cationic guar gum (the ammonium hydroxy-propyl-trimethyl chloride of guar gum) and sodium alginate has been studied. The effects of the mass ratio of them, mixed temperature, balk salt ion concentration, incubation time and pH value on gelation were investigated. It has been observed that there was a gel strength maximum when the mass ratio was 0.6, the mixed temperature was 70°C, the balk salt ion concentration was 1.0 mol·L?1, the incubation time was 30 min and the pH value was 8. Interaction between molecules of these two polysaccharides was investigated by FT-IR spectrometry. Key words cationic guar gum - sodium alginate - gelation - synergism CLC number O 629.12 Foundation item: Supported by the National Natural Science Foundation of China(29574173)Biography: He Dong-bao (1945-), male, Associate professor, research direction: modifying and gelating of natural polysaccharides.
基金Scientific Research(KAKENHI)(C),No.25460958Japan Society for the Promotion of Science,No.20K11513and Adaptable and Seamless Technology Transfer Program through target driven R&D from the Japan Agency for Medical Research and Development.
文摘BACKGROUND The gut-liver axis has attracted much interest in the context of chronic liver disease pathogenesis.Prebiotics such as dietary fibers were shown to attenuate non-alcoholic fatty liver disease(NAFLD)by modulating gut microbiota.Partially hydrolyzed guar gum(PHGG),a water-soluble dietary fiber,has been reported to alleviate the symptoms of various intestinal diseases and metabolic syndromes.However,its effects on NAFLD remain to be fully elucidated.To determine whether treatment with PHGG attenuates NAFLD development in mice through the gut-liver axis.METHODS Seven-week-old male C57BL/6J mice with increased intestinal permeability were fed a control or atherogenic(Ath)diet(a mouse model of NAFLD)for 8 wk,with or without 5%PHGG.Increased intestinal permeability was induced through chronic intermittent administration of low-dose dextran sulfate sodium.Body weight,liver weight,macroscopic findings in the liver,blood biochemistry[aspartate aminotransferase(AST)and alanine aminotransferase(ALT),total cholesterol,triglyceride,free fatty acids,and glucose levels],liver histology,myeloperoxidase activity in liver tissue,mRNA expression in the liver and intestine,serum endotoxin levels in the portal vein,intestinal permeability,and microbiota and short-chain fatty acid(SCFA)profiles in the cecal samples were investigated.RESULTS Mice with increased intestinal permeability subjected to the Ath diet showed significantly increased serum AST and ALT levels,liver fat accumulation,liver inflammatory(tumor necrosis factor-αand monocyte chemotactic protein-1)and fibrogenic(collagen 1a1 andαsmooth muscle actin)marker levels,and liver myeloperoxidase activity,which were significantly attenuated by PHGG treatment.Furthermore,the Ath diet combined with increased intestinal permeability resulted in elevated portal endotoxin levels and activated toll-like receptor(TLR)4 and TLR9 expression,confirming that intestinal permeability was significantly elevated,as observed by evaluating the lumen-to-blood clearance of fluorescein isothiocyanate-conjugated dextran.PHGG treatment did not affect fatty acid metabolism in the liver.However,it decreased lipopolysaccharide signaling through the gut-liver axis.In addition,it significantly increased the abundance of cecal Bacteroides and Clostridium subcluster XIVa.Treatment with PHGG markedly increased the levels of SCFAs,particularly,butyric acid,acetic acid,propionic acid,and formic acid,in the cecal samples.CONCLUSION PHGG partially prevented NAFLD development in mice through the gut-liver axis by modulating microbiota and downstream SCFA profiles.
文摘HGG (Hydroxypropyl guar gum) was synthesized by phase transfer catalysis for the first time. The effects of alkalinity, phase transfer catalyst, etherification, pH value, temperature, reaction time and stirring speed were investigated. An optimal synthetic reaction technology was established, namely, dose of guar gum is 100 g, propylene oxide 40-50 g, HTAC (hexadecyl trimethyl ammonium chloride ) 1.3-1.7 g, pH value 10-10.5, temperature 45-50℃, and reaction time 3-4 hours. The result shows that the improved HGG has high viscosity. Its dissolution speed, content of insoluble residue, colloid light transparency and stability are apparently superior to guar flour.
基金financial support from Institute for Oil Sands Innovation(IOSI)Imperial Oil+3 种基金the Natural Sciences and Engineering Research Council of Canada(NSERC)the Canada Foundation for Innovation(CFI)the Future Energy Systems under the Canada First Research Excellence Fundthe Canada Research Chairs Program to the research work。
文摘As water-based extraction technologies for producing bitumen from oil sands have received increasing environmental concerns,developing non-aqueous extraction(NAE)technique is of both fundamental and practical importance.However,the relatively high concentration of fine solids trapped in the extracted bitumen presents an obstacle for pipeline transport as well as upgrading and refining downstream.This research attempts to provide a solution to fine solids removal without using synthetic additives or affecting bitumen recovery from NAE process.Herein,naturally hydrophilic additives(i.e.,water and high molecular weight guar gum(HGG)produced from Cyamopsiste tragonolobuosr L.Taup.)were introduced to promote the settling of fine solids suspended in bitumen-solvent solution,and the effects of solvents(i.e.,toluene,cyclohexane and their mixtures)were systematically investigated.Aggregate size distribution analyzed by the focused beam reflectance measurements confirmed that the addition of water and HGG could promote the agglomeration and settling of fine solids in all solvents studied.However,the size range and quantity of the agglomerates vary significantly with the solvent's aromatic character.Solvent mixtures demonstrate a superior performance on removing fine solids from bitumen over single solvent.Specifically,in a 3:2 toluene/cyclohexane mixture,the solid content was lowered from 0.66 wt%to 0.09 wt%.
文摘The reduced viscosity of polymer guar gum solutions containing a certain concentration of sodium dodecyl benzene sulfonate （SDBS） was measured. It has been found that the Huggins coefficient kH of polymer solutions is very sensitive to the concentration of the surfactant, CSDBS, in solutions. If CSDBS is lower than CMC, the critical micelle concentration of SDBS, kH increases rapidly with CSDBS. On the other hand, if CSDBS is larger than CMC, kH decreases rapidly with CSDBS. Comparatively, the intrinsic viscosity of polymer solution does not show a notable change with CSDBS. The experimental results indicate that the interchain association of polymer guar gum in solution is greatly associated with SDBS interacted with polymer chains through hydrogen bonds. However, the effect of SDBS upon the intrachain association of polymer guar gum solution is negligible, presumably due to the fact that guar gum is a slightly stiffened random-coil chain polymer.
文摘The tetrahedral borate ion can crosslink with polymer guar gum in aqueous solutions. If the concentration of guar gum is less than 0.045 g/dL, the intramolecular interaction between guar gum and borate ion increases due to the formation of crosslinks. As a result, the polymer chains of guar gum in solution shrink in size and the reduced viscosity of polymer solution decreases accordingly. On the other hand, if the concentration of guar gum is greater than 0.045 g/dL, the intermolecular interaction becomes apparent due to the same reason. The polymer chains, therefore, associate together and the reduced viscosity of polymer solution increases considerably. According to this technique, the critical concentration c^＊, presented by de-Gennes, is determined successfully.
基金supported by the Halliburton Energy Services,Inc.,USA
文摘Guar [Cyamopsis tetragonoloba （L.） Taub.] is one of the most important industrial crops due to its richness in gum. Understanding the inheritance of gum content is a key to its successful genetic improvement. Gum content expression is reported to be controlled by additive, dominant, and epistatic effects, and modified by the environment, fg%, a relative gum content calculated by comparing with the gum content of Kinman was used as gum content （%） in this experiment. Reciprocal crosses of two lines of guar, PI 217923 and Lewis, were made to study the heritability of gum content （fg%）. fg% of four plant introductions and four commercial varieties were studied in Lubbock in 1999-2002. Estimates of broadsense heritability （h^2 b,s.） of fg% in Lewis x PI 217923 and PI 217923 x Lewis were 75.53 and 52.74%, respectively. Estimates of narrow-sense heritability （h2 n.s.） of fg% were 40.00 and 29.00% thr Lewis x PI 217923 and PI 217923 x Lewis, respectively. At least one pair of genes were estimated to control the fg% expression in these two crosses, Significant differences of fg% were found among these eight entries. PI 217923 was found to have the highest fg% among the eight entries.
文摘We prepared, characterized and studied the biodistribution of tamoxifen citrate (TMX) loaded cross-linked guar gum (GG) nanoparticles (NPs). NPs were prepared via a single step emulsion process and particle size evaluated. The extent of tissue distribution and retention following oral administration of TMX loaded GG NPs and TMX tablet in female albino mice was analyzed over a period of 48 hours. Till 48 hours, the particles remained detectable in both mammary and ovary tissue (estrogen receptors). Uptake and retention of TMX from NPs and tablet in mammary gland and ovary tissue changed with time. Results showed that the uptake and retention of NPs was more in the mammary gland between 24 - 48 hours (11.2% at 24 h;4.65% at 48 h). As mammary gland is the target organ in breast cancer therapy, it may be concluded that the cross-linked GG NPs are capable of releasing the drug at the target and minimize the uptake and retention in non target tissue, the ovary (7.98% at 24 h;1.9% at 48 h). Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) with time were measured. No abnormal changes in the liver enzymes were observed. GG NPs under study can be used as a drug carrier system for treating cancer.
文摘Natural gums can be tailored and used for the removal of toxic dyes like crystal violet via grafting techniques. However, grafting via microwave irradiation showed both higher yield and fast reaction kinetics as compared to conventional grafting. Silane modified nanoclay has been used to prepare acrylic acid grafted guar gum nanocomposites via microwave irradiation technique. The grafting was confirmed via infrared spectroscopy while XRD diffractograms suggested exfoliation of modified nanoclay in guar gum grafted acrylic acid. The reaction kinetic parameters have been optimized. The effect of nanoclay on swelling characteristics has been examined. The sensitivity of pH on swelling capabilities has also been assessed. The efficiency of the superabsorbent nanocomposite on the absorption of crystal violet dye has been studied. The superabsorbent nanocomposite loaded with 1.75% modified nanocaly was found to be optimal concentration for the removal of crystal violet dye.
文摘Based on the water quality detection and analysis of guar gum waste liquid,as well as the data of experiments on the treatment of waste liquid under different viscosity and pH conditions,the influencing factors of solid-liquid separation under conventional"coagulation+filtration"treatment process are studied.Under the conventional"coagulation+filtration"treatment process,the viscosity of guar gum waste liquid is lower than 3 mPa·s;the pH is 6-7.5;the filtration accuracy is not lower than 20μm,which can meet better treatment conditions.This experimental study provides an experimental basis for the optimal design of the treatment process of guar gum waste liquid.
