Oxidation of Partially Hydrolyzed Polyacrylamide from Polymer Flooding Processes Using Fenton Reagents

The degradation of partially hydrolyzed polyacrylamide(HPAM) found in alkaline/surfactant/polymer flooding sewage was investigated using Fenton-type reagents. Different Fenton reagent treatments for HPAM degradation were compared. The effects of pH, hydrogen peroxide(H_(2)O_(2)), ferrous ion(Fe^(2+)), and tartaric ion(C_(4)H_(4)O_(6)^(2-)) concentrations were studied. The degradation reaction occurred within a wide range of pH(3–9). The HPAM degradation performance of photo-Fenton processes using solar light and UV were compared with that of the Fenton process. The degradation rate was found to be strongly dependent on the H_(2)O_(2)/Fe^(2+)/C_(4)H_(4)O_(6)^(2-)molar ratio. The HPAM degradation efficiency was 90%, and the chemical oxygen demand removal efficiency was 85%. HPAM could be degraded into a compound with a lower molecular weight, but it was difficult to achieve complete mineralization to CO_(2). The presence of intermediate products hindered further oxidation in the Fenton process.

Partially hydrolyzed guar gum in pediatric functional abdominal pain

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.

Effect of Dietary Supplementation with Hydrolyzed Wheat Gluten on Growth Performance, Cell Immunity and Serum Biochemical Indices of Weaned Piglets (Sus scrofa)

To investigate the effects of dietary supplementation with hydrolyzed wheat gluten （HWG） on growth performance, cell immunity and serum biochemical indices of weaned piglets, 160 crossed （Large White×andrace） and weaned piglets were randomly divided into 4 treatments with 4 replicates of 10 piglets each. The piglets in each treatment were fed an experimental diet containing either 0 g kg-1 HWG （control group）, 30 g kg-1 HWG （3% HWG group）, 50 g kg-1 HWG （5% HWG group）, or 2.5 g kg-1 glycyl-L-glutamine （0.25% Gly-Gln group）. The results showed that the diarrhea rates in 3% HWG and 5% HWG groups were significantly lower than in control group from d 1 to 14 （P〈0.05）, while the average daily gain （ADG） in each of two groups was increased （P〉0.05）. When compared with control group, dietary supplementation with 3% HWG increased the ratio of CD4＋：CD8＋ and the ratio of serum albumin and globulin concentrations （A：G） on d 14 and 28, as well as the proliferation of T- and B-lymphocytes （P〉0.05） on d 28. In addition, on d 14 and 28, the A：G ratio in 5% HWG group was significantly higher than in control group （P〈0.05）, while the ratio of CD4＋：CD8＋ increased slightly （P〉0.05）. Interestingly, 0.25% Gly-Gln group had higher proportion of CD3＋ （P〉0.05） and CD4＋ （P〈0.05） on d 14 than control group, but growth performances of 0.25% Gly-Gln group were negatively affected at all experiment stages. These results suggested that HWG might improve the growth performance of piglets by strengthening cell immunity and decreasing the occurrence of diarrhea during the prophase after weaning.

Partially hydrolyzed guar gum attenuates non-alcoholic fatty liver disease in mice through the gut-liver axis

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.

Effect of salt solutions on chain structure of partially hydrolyzed polyacrylamide

The effect of salt solutions(NaCl,Na2SO4 and CaCl2) on the conformational properties of partially hydrolyzed polyacrylamide(HPAM) was investigated by using static laser light scattering(SLLS).The special interaction between CaCl2 solution and HPAM was also researched.Experimental results show that the chain structure of HPAM is interrelated with the charge density,the kind and the concentration of salt solutions.The mean-square radius of gyration(Rz) and the second virial coefficient(A2) of HPAM decrease with increasing concentration of salt solutions,and the salt effect tends towards the maximum when the concentration of salt solution is increased to some amount.

Separation of diaspore from bauxite by selective flocculation using hydrolyzed polyacrylamide

Selective flocculation is a new method to solve the problem of China's bauxite de-silication besides flotation and reverse flotation. The method of selective flocculation of bauxite using hydrolyzed polyacrylamide as flocculant was experimented and evaluated. The results of diaspore and kaolinite single mineral settling tests show that the difference between settlement yield of kaolinite(settling 15 min) and diaspore(settling 3 min) increases from 16% to 60% by adding flocculant at pH=7. Results of selective flocculation experiment of bauxite show that the higher concentrate grade(65.75) and Al-Si ratio(7.34) could be obtained with sodium carbonate as dispersant compared with sodium hexametaphosphate; under the action of flocculating agent, the concentrate grade and Al-Si ratio increase to 67.99 and 9.01. These results could meet the requirements of Bayer production, and the simpler process was expected to cost far less than traditional flotation method and a promising de-silication method of bauxite.

INTERACTION OF COMPONENTS IN PETROLEUM CARBOXYLATE/ALKALINE/HYDROLYZED POLYACRYLAMIDE FLOODING SYSTEM

The IFTs(Interfacial tension)of petroleum carboxylate/alkaline/HPAM(Hydrolyzed polyacrylamide)flooding system with Daing crude oil and the effects of petroleum carboxylate and alkaline on viscoaity of HPAM solution were studied.There exists remarkable synergism between HPAM and petroleum carboxylate,and the introduction of HPAM into petroleum carboxylate/alka- line system leads the lowering of IFTs against Daqing crude oil,The introduction of petroleum carboxylate into solution of HPAM also leads the decreasing of viscosity,but the extent of viscosity decreasing is much lower than that caused by inorganic salts such as NaCl and CaCl_2.

Hypoallergenicity of a thickened hydrolyzed formula in children with cow’s milk allergy

BACKGROUND Allergy to cow’s milk is the most frequent allergy occurring in infants and young children.The dietary management of these patients consists of the elimination of any cow’s milk proteins from the diet,and for formula-fed infants,the substitution of the usual infant formula with an adapted formula that is generally based on extensively hydrolyzed cow’s milk proteins.The American Academy of Pediatrics has established specific criteria to confirm the hypoallergenicity of a formula intended for these children.AIM To assess the hypoallergenicity of a new thickened extensively hydrolyzed casein-based formula (TeHCF) in children with cow’s milk allergy (CMA).METHODS Children diagnosed with CMA through a double-blind placebo-controlled food challenge (DBPCFC) were randomly administered increased doses of a placebo formula or the TeHCF [Allernova,new thickener including fibres (Novalac)] under double-blind conditions and medical surveillance on two separate days.Otherwise,both of these formulas and a cow’s milk-based formula were randomly introduced to children who were highly suspected of having CMA on three separate days.Immediate and late reactions occurring after the introduction of any of these formulas were thoroughly recorded by the physician at the hospital and reported by parents to the physician after hospital discharge,respectively.If the children tolerated the TeHCF during the DBPCFC,they were exclusively fed this formula during a 3-mo period where potential allergic symptoms,anthropometric parameters,as secondary outcomes,and adverse events were registered.The Cow’s Milk-related Symptoms Score (CoMiSSTM) was assessed and anthropometric parameters were compared to World Health Organization (WHO) reference data.RESULTS Of the 30 children included in the study,the CMA diagnosis of 29 (mean age: 8.03 ± 7.43 mo) patients was confirmed by a DBPCFC.The children all tolerated the TeHCF during both the challenge and the subsequent 3-mo feeding period,which they all completed.During the latter period,the CoMiSSTM remained at a very low level,never exceeding its baseline value (1.4 ± 2.0),growth parameters were within WHO reference standards and no adverse event related to the TeHCF was reported.Over the first week of this period,the proportion of patients with digestive discomfort significantly decreased from 20.7%(6/29) to 3.4%(1/29),P = 0.025.The proportion of satisfaction with the overall effect of the formula reported by the parents and investigator was high,as was the formula acceptability by the child.CONCLUSION The new TeHCF meets the hypoallergenicity criteria according to the American Academy of Pediatrics standards,confirming that the tested TeHCF is adapted to the dietary management of children with CMA.Moreover,growth was adequate in the included population.

Enhanced Redispersibility of Cellulose Nanocrystals in Water via Surface Adsorption of Hydrolyzed Sugars from Corresponding Cellulose Nanocrystal Fabrication

Generally,hydrogen bonds are formed between cellulose nanocrystals(CNCs)during their water removal and drying,leading to the irreversible aggregation of CNCs,and thus a poor water-redispersibility.The present study demonstrated a novel approach that involved using hydrolyzed sugars generated from the corresponding CNC production as redispersing agents to enhance the redispersibility of CNCs.Experimental data indicated that hydrolyzed sugars can be adsorbed onto CNCs through ethanol precipitation.The oven-dried CNCs onto which hydrolyzed sugars were adsorbed via ethanol precipitation were homogeneously redispersed in water.The redispersed CNCs showed the particle size distribution,Zeta potential,and thermal decomposition properties similar to those of the CNCs without drying.This method may improve the use of hydrolyzed sugars obtained in the hydrolysate from the corresponding CNC production,as well as facilitate the transportation and storage of CNCs.

Effect of high-protein peptide-based formula compared with isocaloric isonitrogenous polymeric formula in critically ill surgical patient

BACKGROUND Malnutrition is common in critically ill patients,and it is associated with an increased risk of complications.Early enteral nutrition with adequate caloric and protein intake is critical nevertheless it is difficult to achieve.Peptide-based formulas have been shown to be beneficial in patients with feeding intolerance.However,there are limited studies showing the efficacy and safety of high-protein peptide-based formula in critically ill surgical patients.AIM To determine the effects of a high-protein peptide formulation on gastrointestinal tolerance,nutritional status,biochemical changes,and adverse events in patients in the surgery intensive care unit(SICU)compared to an isocaloric isonitrogenous standard polymeric formulation.METHODS This study was a multi-center double-blind,randomized controlled trial.We enrolled adult patients in the surgical intensive care unit,age≥15 years and expected to receive enteral feeding for at least 5-14 d post-operation.They were randomly assigned to receive either the high-protein peptide-based formula or the isocaloric isonitrogenous standard formula for 14 d.Gastric residual volume(GRV),nutritional status,body composition and biochemical parameters were assessed at baseline and on days 3,5,7,9,11,and 14.RESULTS A total of 19 patients were enrolled,9 patients in the peptide-based formula group and 10 patients in the standard formula group.During the study period,there were no differences of the average GRV,body weight,body composition,nutritional status and biochemical parameters in the patients receiving peptide-based formula,compared to the standard regimen.However,participants in the standard formula lost their body weight,body mass index(BMI)and skeletal muscle mass significantly.While body weight,BMI and muscle mass were maintained in the peptide-based formula,from baseline to day 14.Moreover,the participants in the peptide-based formula tended to reach their caloric target faster than the standard formula.CONCLUSION The study emphasizes the importance of early nutritional support in the SICU and showed the efficacy and safety of a high-protein,peptide-based formula in meeting caloric and protein intake targets while maintaining body weight and muscle mass.

Hydrolyzed seawater pearl tablet modulates the immunity via attenuating Th1/Th2 imbalance in an immunosuppressed mouse model

OBJECTIVE: To investigate whether Hydrolyzed Seawater Pearl tablet(HSPT) could modulate the Th1/Th2 imbalance in an immunosuppressed mouse model with Th1 to Th2 shift induced by Cyclosporine A(Cs A) which can be used in the clinical treatment of Th2 to Th1 shift diseases, and explore the possible mechanism for the adjuvant therapeutic efficacy of HSPT on recurrent respiratory infections(RRI) and acquired immune deficiency syndrome(AIDS).METHODS: The mice were randomly divided into six groups of five animals each, namely normal group, model group, lentinan polysaccharide tablet(LPT) group and three HPST treated groups. HPST treated groups were administered with HPST(0.51,1.02, 2.04 g/kg) via intragastric gavage(i.g) for 30 consecutive days. LPT used as reference drug for positive control, LPT group was administered with LPT(8.2 mg/kg) for 30 consecutive days. Normal group and model group were received distilled water. The animals in model group, LPT group and HPST treated groups were injected intraperitoneally with Cs A(50 mg/kg) to establish the immunosuppressed mice model with Th1 to Th2 shift on the20 th, 22 nd and 24 th day, one hour after the administration of the respective treatment. Animals were sacrificed one hour after the last administration to collect blood and splenic tissue. The proportion of T cells including CD8+ and CD4+ T cells, Th1 and Th2 in peripheral blood of experimental mice were measured by flow cytometric. The protein level in serum and m RNA level in splenic tissue of experimental mice for interleukin(IL)-2, IL-12, interferon-γ(IFN-γ), IL-4, IL-6, IL-10 and IL-13 were measured by enzyme linked immunosorbent assay and fluorescence quantitative polymerase chain reaction respectively.RESULTS: HSPT elevated the proportion of T cells including both CD8+ and CD4+ T cells, in which the proportion of Th1 and Th2 cells increased, while the ratio of Th1/Th2 cells decreased in peripheral blood of the immunosuppressed mouse model with Th1 to Th2 shift induced by Cs A. Furthermore,HSPT elevated both protein and m RNA level of Th1-type cytokines IL-2 and IFN-γ, while had no significant effect on protein and m RNA level of Th1-type cytokine IL-12 and Th2-type cytokines IL-4, IL-6, IL-10, IL-13 in mouse model.CONCLUSION: Our findings suggest that HSPT can increase proportion of T cells including both CD8+and CD4+T cells and induce Th2 to Th1 shift in both cells and cytokines, which probably was the mechanism to account for the adjuvant therapeutic efficacy of HSPT on RRI and AIDS.

Function-regeneration of non-porous hydrolyzed-MOF-derived materials

A facile synthetic strategy based on a water-based process is developed for the preparation of metal-organic framework (MOF)-derived materials by revisiting the hydrolyzed non-porous metal-organic frameworks (h-MOF). The poor water stability of MOF has been recognized as key limitations for its commercialization and large-scale applications because the hydrolysis resulted in the complete loss of their functionalities. However, we found that the negative effect of hydrolysis on MOF can be nullified during the heat treatment. As similar to the intact MOF, h-MOF can be used as a precursor for the preparation of MOF-derived materials from porous MOF-derived carbons (MDCs) to MDC@ZnO composites. The property of h-MOF-derived materials is almost equivalent to that of MOF-derived materials. In addition, h-MOF turned the weakness of water instability to the strength of facile water-based process for hybridization. With the demonstration of the hybrid composite between h-MDC@ZnO and reduced graphene oxide (rGO) as a prototype example, it exhibited superior electrochemical performance when evaluated as an electrode material for lithium-ion batteries.

Flesh quality of hybrid grouper(Epinephelus fuscoguttatus♀×Epinephelus lanceolatus♂)fed with hydrolyzed porcine mucosasupplemented low fishmeal diet

Iso-nitrogenous and iso-lipidic diets containing 0%,3%,6%,9%,and 12%hydrolyzed porcine mucosa(namely,HPM0,HPM3,HPM6,HPM9,and HPM12)were prepared to evaluate their effects on the growth performance,muscle nutrition composition,texture property,and gene expression related to muscle growth of hybrid groupers(Epinephelus fuscoguttatus\Epinephelus lanceolatus_).Groupers were fed to apparent satiation at 08:00 and 16:00 every day for a total of 56 days.It was found that the weight gain percentage in the HPM0,HPM3,and HPM6 groups did not differ(P>0.05).The cooking loss and drip loss of the dorsal muscle in the HPM3 group were lower than those in the HPM6 and HPM9 groups(P<0.05).The hardness and chewiness of the dorsal muscle in the HPM3 group were higher than those in the HPM0,HPM9,and HPM12 groups(P<0.05).The gumminess in the HPM3 group was higher than that in the HPM9 and HPM12 groups(P<0.05).The total essential amino acid content of the dorsal muscle in the HPM12 group was higher than that in the HPM0 group(P<0.05).The contents of total n-3 polyunsaturated fatty acid and total n-3 highly unsaturated fatty acid,as well as the ratio of n-3/n-6 polyunsaturated fatty acid in the dorsal muscle was higher in the HPM0 group than in all other groups(P<0.05).The relative expressions of gene myogenic factor 5,myocyte enhancer factor 2c,myocyte enhancer factor 2a,myosin heavy chain,transforming growth factor-beta 1(TGF-b1),and follistatin(FST)were the highest in the dorsal muscle of the HPM3 group.The results indicated that the growth performance of hybrid grouper fed a diet with 6%HPM and 27%fish meal was as good as that of the HPM0 group.When fish ingested a diet containing 3%HPM,the expression of genes TGF-β1 and FST involved in muscle growth were upregulated,and then the muscle quality related to hardness and chewiness were improved.An appropriate amount of HPM could be better used in grouper feed.

Rheology of diluted and semi-diluted partially hydrolyzed polyacrylamide solutions under shear:Experimental studies

Rheological properties of hydrolyzed polyacrylamide(HPAM)solutions were measured in oscillatory and flow shear.In oscillatory shear the storage and loss moduli increased as the concentrations of the solutions increased,but they decreased as salinity increased.The relaxation spectra were plotted using the Kontogiorgos method.As shown in the relaxation spectra,the number of density of segmental units increased at first and then the peaks shifted and split into several as the concentration increased.With salinity increasing,the number of motion units increase and the peaks of segmental units became broader.In flow shear tests,the curves of viscosity versus shear rate were fitted by a power law equation.The result showed that the flow behavior index decreased with increasing concentration,while it generally increased with increasing of salinity.Furthermore,the first normal stress difference increased as the concentration was increased,while it decreased as the salinity was increased.The first normal stress differences measured by the rheometer were compared with the first normal stress differences calculated by the Laun equation and the results showed that Laun equation deviates the experimental results.

酶解乳蛋白对初生仔猪小肠组织学结构及隐窝细胞增殖的影响(英文)

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Nutritional and health benefits of semi-elemental diets: A comprehensive summary of the literature

AIM:To critically review and summarize the literature on nutritional and health outcomes of semi-elemental formulations on various nutritionally vulnerable patient populations who are unable to achieve adequate nutrition from standard oral diets.METHODS:We conducted a comprehensive literature search of Pubmed and Embase databases.We manually screened articles that examined nutritional and health outcomes(e.g.,growth,disease activity,gastrointestinal impairment,mortality,and economic impact)among various patient groups receiving semi-elemental diets.This review focused on full-text articles of randomized controlled clinical trials and other intervention studies,but pertinent abstracts and case studies were also included.Results pertaining primarily to tolerance,digestion,and absorption were summarized for each patient population in this systematic review.RESULTS:Results pertaining primarily to tolerance,digestion,and absorption were summarized for each patient population.The efficacy of semi-elemental whey hydrolyzed protein(WHP)diet have been reported in various nutritionally high risk patient populations including-Crohn’s disease,short bowel syndrome,acute and chronic pancreatitis,cerebral palsy,cystic fibrosis,cerebrovascular accidents,human immunodeficiency virus,critically ill,and geriatrics.Collectively,the evidence from the medical literature indicates that feeding with a semi-elemental diet performs as well or better than parenteral or amino acid based diets in terms of toler-ance,digestion,and nutrient assimilation measures across various disease conditions.CONCLUSION:Based on this comprehensive review of the literature,patient populations who have difficulty digesting or absorbing standard diets may be able to achieve improved health and nutritional outcomes through the use of semi-elemental WHP diets.

酸水解植物蛋白热反应制备烤牛肉香基的工艺研究

研究影响酸水解植物蛋白热反应制备烤牛肉香基的因素,同时考察不同反应条件对酸水解植物蛋白热反应制备烤牛肉香基的影响。在单因素初步试验的基础上,以烤牛肉香基的感官评分值为考察指标,通过单因素试验、正交试验及方差分析,考察各加工条件对酸水解植物蛋白热反应制备烤牛肉香基的影响,并采用顶空固相微萃取和气相色谱-质谱联用技术对最优条件下反应产物的挥发性物质进行检测分析。结果表明:添加酸水解植物蛋白126 g、I+G 2.5 g、L-谷氨酸1.0 g、L-半胱氨酸盐酸盐5.0 g、L-脯氨酸1.0 g、甘氨酸5.0 g、盐酸硫胺2.5 g、葵花子油4.0 g、还原糖0.075 mol,热反应条件为反应温度115℃、反应时间90 min、反应p H值7.5时制备的烤牛肉香基风味浓厚、圆润、真实、持久,香气评分值可达到95.86。对挥发性物质分析表明,最优条件下制备的烤牛肉香基中主要香气成分为吡嗪类、酮类、酯类、醇类、醛类化合物和一些杂环化合物。产物中含有的吡嗪类、酮类、醇类、醛类等化合物是重要的烤香和肉香味关键贡献性成分,烤牛肉香味特征明显。

Rheological properties of salt-tolerant HPAM solutions with ultrahigh molecular weight

The rheological properties of salt-tolerant partially hydrolyzed polyacrylamide(HPAM)solutions with molecular of 2.5×107 g/mol at different concentrations were measured in steady-state shear flow mode by Haake Rheostress 150 rheometer.Three constitutive equations(Oldroyd four constant model,Guesekus model and FENE-P model) were used for describing the apparent viscosity and first normal stress difference.The apparent viscosity of salt-tolerant HPAM solutions appears a first Newtonian zone when the shear rate is approximately lower than 0.2 s-1.At high shear rate,the HPAM solutions show shear-thinning and elasticity.The results show that the FENE-P model has the best agreement between theoretical and experimental data within the available shear rate range.The material parameters are useful for numerical analysis of polymer solution flow fields.

Deformation of Linked Polymer Coils

Linked polymer solution (LPS) is defined as the solution of linked polymer coils (LPCs) dispersed in water, composed of low concentration partially hydrolyzed polyacrylamide (HPAM) and aluminum citrate (crosslinker). In the work, the conformational changes of LPCs under different conditions were investigated by the methods of membrane filtering under low pressure, dynamic light scattering and core flooding experiments. The results showed that in some conditions the LPCs could be compressed mechanically to 1/158.5 of their original volume because of relatively lower HPAM cross-linking. The hydration property of LPCs was similar to that of normal polymer coils. The deformation of LPCs was more restricted than that of ordinary polymer coils under the flow shear stress or the shift of hydration equilibrium caused in the variation of the electrolyte concentration which is responsible for the effective plugging in the throats of porous media when LPCs are used for deep diverting.

Chromium-Containing Organic Fertilizers from Tanned Hides and Skins: A Review on Chemical, Environmental, Agronomical and Legislative Aspects

A category of chromium (Cr)-containing fertilizers is represented by the fertilizers deriving from byproducts of tanning process. Their use is widespread because of their good agronomic response due to the high content of slow release or- ganic nitrogen (N) and carbon (C). They do not represent an environmental hazard because only the non-toxic form of Cr(III) is present. Productive processes may involve chemical, enzymatic or thermal hydrolysis. The final product is characterized by different contents of peptides and free amino acids depending on the type of hydrolysis. Legislation concerning Cr-containing fertilizers is controversial because often do not consider any scientific evidences;nevertheless, the European Union, the United States and countries as Italy, do not set the restriction to Cr(III) and generally only the presence of the toxic form, Cr(VI), is limited. Depending on its two main oxidation forms, Cr issue has been studied for many years. Several authors confirmed that Cr(VI) is carcinogenic, while Cr(III) is an essential trace element in human and animal diet. In soil Cr(III) has low mobility, whereas Cr(VI) is highly water soluble. However Cr(VI) in soil is quickly reduced to Cr(III);on the contrary oxidation of Cr(III) to Cr(VI) is rarely possible because particular conditions must occur. Only a very small fraction of Cr in soil is available to plant uptake and its translocation in edible parts is limited because it is immobilized in roots as Cr(III). Therefore risks of environmental pollution using these fertilizers are negligible;on the contrary they have positive environmental and agronomical effects. The aim of this review is to deal with the category of the organic fertilizers containing Cr derived from tannery processes focusing on its chemical, productive, legislative, environmental and agronomical aspects. Special attention is given to the ambiguous issue of Cr briefly summarizing the most important studies of the last forty years.