Gossypol acetic acid regulates leukemia stem cells by degrading LRPPRC via inhibiting IL-6/JAK1/STAT3 signaling or resulting mitochondrial dysfunction

BACKGROUND Leukemia stem cells(LSCs)are found to be one of the main factors contributing to poor therapeutic effects in acute myeloid leukemia(AML),as they are protected by the bone marrow microenvironment(BMM)against conventional therapies.Gossypol acetic acid(GAA),which is extracted from the seeds of cotton plants,exerts anti-tumor roles in several types of cancer and has been reported to induce apoptosis of LSCs by inhibiting Bcl2.AIM To investigate the exact roles of GAA in regulating LSCs under different microenvironments and the exact mechanism.METHODS In this study,LSCs were magnetically sorted from AML cell lines and the CD34+CD38-population was obtained.The expression of leucine-rich pentatricopeptide repeat-containing protein(LRPPRC)and forkhead box M1(FOXM1)was evaluated in LSCs,and the effects of GAA on malignancies and mitochondrial RESULTS LRPPRC was found to be upregulated,and GAA inhibited cell proliferation by degrading LRPPRC.GAA induced LRPPRC degradation and inhibited the activation of interleukin 6(IL-6)/janus kinase(JAK)1/signal transducer and activator of transcription(STAT)3 signaling,enhancing chemosensitivity in LSCs against conventional chemotherapies,including L-Asparaginase,Dexamethasone,and cytarabine.GAA was also found to downregulate FOXM1 indirectly by regulating LRPPRC.Furthermore,GAA induced reactive oxygen species accumulation,disturbed mitochondrial homeostasis,and caused mitochondrial dysfunction.By inhibiting IL-6/JAK1/STAT3 signaling via degrading LRPPRC,GAA resulted in the elimination of LSCs.Meanwhile,GAA induced oxidative stress and subsequent cell damage by causing mitochondrial damage.CONCLUSION Taken together,the results indicate that GAA might overcome the BMM protective effect and be considered as a novel and effective combination therapy for AML.

Scale-up of biomass conversion using 1-ethyl-3-methylimidazolium acetate as the solvent

This scale-up study demonstrated the feasibility of an ionic liquid(IL)pretreatment process at 40 kg scale,using the IL 1-ethyl-3-methylimidazolium acetate([C2C1Im][OAc])as the solvent.The pretreatment was followed by enzymatic hydrolysis through which the process efficiency for biomass conversion to monomeric sugars was determined.The results show that 43 wt%of switchgrass was dissolved in IL after 2 h of pretreatment at 160℃ with 15 wt%solid loading.A 120 h enzymatic hydrolysis of the pretreated switchgrass results in 96%glucan and 98%xylan conversion.[C2C1Im][OAc]pretreatment has been successfully scaled up to 40 kg with improved sugar titers and yields relative to bench scale(6 kg).The mass flow of the overall process was established and the major scale-up challenges of the process were identified.

Synthesis of Phenyl Acetate from Phenol and Acetic Anhydride over Synthetic TS-1 Containing Template

In this article, phenyl acetate was synthesized from phenol and acetic anhydride over titanium silicalite-1, in which the organic structure-directing agents were immobilized(TS-1-U). The reaction conditions were specified at a phenol to acetic anhydride molar ratio of 1:1.2, a catalyst dosage of 6 m%, and a reaction temperature of 70 ℃. A total of 96.5% of phenol was converted to phenyl acetate without producing any byproducts after 2.5 h of reaction. Besides, although the catalyst deactivation is inevitable, TS-1-U could be recycled for at least four times.

Synthesis and Crystal Structure of Tetraaquacopper(II) Bis(5-fluorouracil-1-acetate) Tetrahydrate

The title compound, [Cu（C6H4N2O4F）2（H2O）4].4（H2O） I, has been hydrothermally synthesized and structurally determined by single-crystal X-ray diffraction method. It crystallizes in monoclinic, space group P21/c with a = 8.3041（17）, b = 12.045（2）, c = 11.077（2） A, β = 92.567（3）°, V= 1106.8（4） A^3, Mr = 581.89, Z= 2, Dc = 1.746 g/cm^3, F（000） = 598,μ（MoKa） = 1.090 mm^-1, the final R = 0.0296 and wR = 0.0806 for 3195 observed reflections with Ⅰ 〉 2σ（Ⅰ）. In the centrosymmetric compound I, each Cu（Ⅱ） ion is coordinated by six O atoms from two 5-fluorouracil-1-acetate anions and four water molecules, forming a six-coordinated octahedral environment. N-H…O and O-H…O hydrogen-bonding interactions are observed in the structure, leading to the formation of a three-dimensional network.

Induction of CD4＋CD25＋Foxp3＋ regulatory T cell response by glatiramer acetate in type 1 diabetes

Glatiramer acetate （GA） is an immunomodulatory peptide drug used to treat multiple sclerosis. Its treatment effect has been expanded to other autoimmune conditions such as uveoretinitis, inflammatory bowel disease, graft re- jection and hepatic fibrosis. Here, we report that GA was effective in altering the clinical course of diabetes in cyclo- phosphamide （CY）-potentiated non-obese diabetic （CY-NOD） mice. Treatment with GA significantly reduced the dia- betic rate in the mice and ameliorated insulitis, which coincided with increased CD4＋CD25＋Foxp3＋ T cell response in treated mice. GA treatment led to increased expression of transcription factor Foxp3 and elevated production of interleukin-4 （IL-4） both in vivo and in vitro. It was evident that the effect of GA on up-regulation of Foxp3 was me- diated partially through IL-4. IL-4 was found to maintain Foxp3 expression and regulatory function of CD4＋CD25＋ regulatory T cells （Tregs）. This study provides new evidence that GA has treatment potential for type 1 diabetes through the induction of Tregs and that increased IL-4 production is partially responsible for the enhanced Treg＇s function in GA treatment.

新型醛糖还原酶抑制1-乙酰基-1H-吲哚-3-乙酸酯的合成及其抑制活性

醛糖还原酶抑制剂(ARIs)抑制多元醇途径的醛糖还原酶是治疗糖尿病并发症的重要策略。以2-氯苯甲酸为起始原料,在碱性条件下经铜催化,与甘氨酸反应生成氯代邻羧基苯基甘氨酸,再与乙酸酐反应,生成N-乙酰基邻羧基苯甲酸。然后在吡啶催化下合环,生成1-乙酰基-^(1)H-吲哚-3-乙酸酯(AIA),总收率为79.0%,纯度为99.0%。通过^(1)H NMR、^(13)C NMR和MS(ESI)对其结构进行表征,并对该化合物的的醛糖还原酶抑制活性进行测定,IC 50=9.4×10^(-2)μM。

Isoimperatorin alleviates acetic acid-induced colitis in rats

Objective:To investigate the effect of isoimperatorin on histopathological and biochemical changes in acetic acid-induced colitis rats.Methods:Colitis was induced by intracolonic administration of acetic acid solution(4%v/v)in rats.Rats were divided into six groups including the sham group,the negative control group,the dexamethasone-treated group,and the groups treated with isoimperatorin(0.1,1,and 10 mg/kg/d by gavage).The treatments were administered for three days and then colonic status was assessed by macroscopic,histopathological,and biochemical analyses.Results:Isoimperatorin significantly alleviated colonic damage in a dose-dependent manner and improved histological changes in rats with acetic acid-induced colitis.It also significantly reduced myeloperoxidase,TNF-α,IL-1β,and malodialdehyde levels.Conclusions:Isoimperatorin alleviates acetic acid-induced colitis in rats and may be a potential therapeutic agent for the treatment of colitis.

Impact of Ionic Liquid 1-Ethyl-3-Methylimidazolium Acetate Mediated Extraction on Lignin Features

This study aims at investigating the impact of ionic liquid extraction on lignin structure by studying the mechanism of lignin depolymerization in 1-ethyl-3-methylimidazolium acetate EMIM[OAc]) and comparing it with that of organosolv and milled wood methods. Ionic liquid mediated lignin (ILL) using EMIM[OAc]), ethanol organosolv lignin (EOL) and milled wood lignin (MWL) were isolated from Typha capensis (TC) and subjected to several analytical characterizations. Experimental data shows that ILL exhibited a relatively lower degree of condensation, lower aromatic C-C structures and a higher aliphatic OH with values of 0.42/Ar, 1.94/Ar and 1.33/Ar moieties compared with EOL values of 0.92/Ar, 2.22/Ar and 0.51/Ar moieties respectively. The ILL was depolymerized under mild conditions giving relatively higher β-aryl ether linkages content, higher molecular mass, and exhibited closer structures and reactivity to native lignin than EOL. These insights on TC lignin depolymerization in EMIM[OAc]) acetate may contribute to better value-addition of lignocellulosic biomass.

苦参总黄酮对醋酸铅诱导小鼠睾丸间质细胞氧化应激的改善作用及对Keap1/Nrf2信号通路的影响

目的:观察苦参总黄酮(SF)对醋酸铅(LA)诱导的小鼠睾丸间质细胞TM3氧化应激的改善作用及其对KELCH状ECH相关蛋白1(Keap1)/细胞中核因子E2相关因子2(Nrf2)信号通路的影响,探讨SF改善由LA诱导的TM3细胞氧化应激的相关作用机制。方法:利用噻唑蓝(MTT)法检测不同浓度(0、10、20、50和80µmol·L^(-1))LA和不同浓度(0、12.5、25.0、50.0和80.0 mg·L^(-1))SF分别干预24 h后的TM3细胞存活率;将TM3细胞随机分为空白对照组、LA组、LA+低剂量SF组、LA+中剂量SF组和LA+高剂量SF组。除空白对照组外,其他各组均采用50µmol·L^(-1)LA诱导TM3细胞24 h建立TM3细胞氧化应激模型,其中LA+低剂量SF组、LA+中剂量SF组和LA+高剂量SF组TM3细胞再分别给予12.5、25.0和50.0 mg·L^(-1)SF。利用MTT法检测TM3细胞存活率;WST-1法和硫代巴比妥酸(TBA)法检测TM3细胞中超氧化物歧化酶(SOD)活性和丙二醛(MDA)水平;Western blotting法检测Nrf2、Keap1和含半胱氨酸的天冬氨酸蛋白水解酶9(Caspase-9)蛋白表达水平。结果:MTT法检测,与0µmol·L^(-1)LA组比较,10、20、50和80µmol·L^(-1)LA组TM3细胞存活率明显降低(P<0.01);与0 mg·L^(-1)SF组比较,12.5、25.0、50.0和80.0 mg·L^(-1)SF组TM3细胞存活率明显降低(P<0.05或P<0.01);与LA组比较,LA+低剂量SF组、LA+中剂量SF组和LA+高剂量SF组TM3细胞存活率明显升高(P<0.01);WST-1法和TBA法检测,与LA组比较,LA+低剂量SF组、LA+中剂量SF组和LA+高剂量SF组TM3细胞中SOD活性明显升高(P<0.01),MDA水平明显降低(P<0.01);Western blotting法检测,与LA组比较,LA+低剂量SF组、LA+中剂量SF组和LA+高剂量SF组TM3细胞中Nrf2蛋白表达水平明显升高(P<0.01),Keap1和Caspase-9蛋白表达水平明显降低(P<0.01)。结论:SF对LA诱导TM3细胞氧化应激具有一定改善作用,并可降低TM3细胞中Keap1蛋白表达水平,升高TM3细胞中Nrf2蛋白表达水平。

应用注射用醋酸亮丙瑞林微球治疗的特发性中枢性性早熟女童血清胰岛素样生长因子1水平的变化及其与生长速度的关系

目的探讨应用注射用醋酸亮丙瑞林微球治疗的特发性中枢性性早熟(ICPP)女童血清胰岛素样生长因子1(IGF-1)水平的变化及其与生长速度的关系。方法回顾性分析2019年1月至2021年1月在北京积水潭医院儿科门诊诊断为ICPP的女童,从中筛选出仅应用注射用醋酸亮丙瑞林微球治疗且持续治疗1年以上的女童共42例。收集其治疗前、治疗6个月及1年后复查的病历资料,对比治疗前后身高、骨龄、骨龄预测终身高及IGF-1等指标变化,分析IGF-1水平变化与生长速度的关系。结果治疗6个月及1年后骨龄预测终身高高于治疗前[(158±3)、(159±4)cm比(156±4)cm],差异均有统计学意义(均P<0.05);治疗1年后患儿身高增长速度明显慢于治疗前、IGF-1年龄范围的标准差明显低于治疗前[(2.8±1.3)cm/6个月比(3.6±1.1)cm/6个月、-0.16(-0.42,0.42)比0.86(0.24,1.84)],差异均有统计学意义(均P<0.05)。治疗1年后患儿身高增长速度与骨龄进展速度的延缓程度及雌二醇下降程度呈正相关(r=0.483,P=0.020;r=0.424,P=0.049),与IGF-1的变化程度无明显相关性(r=0.405,P=0.061)。结论ICPP女童应用注射用醋酸亮丙瑞林微球治疗1年后身高增长速度及血清IGF-1水平均显著下降,身高增长速度与骨龄延缓控制程度及雌激素下降程度呈正相关,与IGF-1水平变化无明显相关性。

Aurantiamide Acetate from Stems of Zanthoxylum Dissitum Hemsley

The genus Zanthoxylum (Rutaceae) is comprised of about 50 species in China.Zanthoxylum dissitum Hems-ley, locally called 'Shanpipa', has been used to treat pains in the loin,limbs and arthritis in Chinese folk medicine. Our previous study reported the isolation andidentification of five quinoline alkaloids . In this continuing study on the chemcial constituentsof Zanthoxylum dissitum Hemsley, a phenylalanine derivative was obtained .

1,3-Bis(2-chloroethyl)-1-nitrosourea enhances the inhibitory effect of Resveratrol on 5-fluorouracil sensitive/resistant colon cancer cells

AIM:To study the mechanism of 5-fluorouracil(5-FU)resistance in colon cancer cells and to develop strategies for overcoming such resistance by combination treatment.METHODS:We established and characterized a 5-FU resistance(5-FU-R)cell line derived from continuous exposure(25μmol/L)to 5-FU for 20 wk in 5-FU sensitive HCT-116 cells.The proliferation and expression of different representative apoptosis and anti-apoptosis markers in 5-FU sensitive and 5-FU resistance cells were measured by the MTT assay and by Western blotting,respectively,after treatment with Resveratrol(Res)and/or 1,3-Bis(2-chloroethyl)-1-nitrosourea(BCNU).Apoptosis and cell cycle arrest was measured by 4',6'-diamidino-2-phenylindole hydrochloride staining and fluorescence-activated cell sorting analysis,respectively.The extent of DNA damage was measured by the Comet assay.We measured the visible changes in the DNA damage/repair cascade by Western blotting.RESULTS:The widely used chemotherapeutic agents BCNU and Res decreased the growth of 5-FU sensitive HCT-116 cells in a dose dependent manner.Combined application of BCNU and Res caused more apoptosis in5-FU sensitive cells in comparison to individual treatment.In addition,the combined application of BCNU and Res caused a significant decrease of major DNA base excision repair components in 5-FU sensitive cells.We established a 5-FU resistance cell line(5-FU-R)from 5-FU-sensitive HCT-116(mismatch repair deficient)cells that was not resistant to other chemotherapeutic agents(e.g.,BCNU,Res)except 5-FU.The 5-FU resistance of 5-FU-R cells was assessed by exposure to increasing concentrations of 5-FU followed by the MTT assay.There was no significant cell death noted in5-FU-R cells in comparison to 5-FU sensitive cells after5-FU treatment.This resistant cell line overexpressed anti-apoptotic[e.g.,AKT,nuclear factorκB,FLICE-like inhibitory protein),DNA repair(e.g.,DNA polymerase beta(POL-β),DNA polymerase eta(POLH),protein Flap endonuclease 1(FEN1),DNA damage-binding protein 2(DDB2)]and 5-FU-resistance proteins(thymidylate synthase)but under expressed pro-apoptotic proteins(e.g.,DAB2,CK1)in comparison to the parental cells.Increased genotoxicity and apoptosis were observed in resistant cells after combined application of BCNU and Res in comparison to untreated or parental cells.BCNU increased the sensitivity to Res of 5-FU resistant cells compared with parental cells.Fifty percent cell death were noted in parental cells when 18μmol/L of Res was associated with fixed concentration(20μmol/L)of BCNU,but a much lower concentration of Res(8μmol/L)was needed to achieve the same effect in 5-FU resistant cells.Interestingly,increased levels of adenomatous polyposis coli and decreased levels POL-β,POLH,FEN1 and DDB2 were noted after the same combined treatment in resistant cells.CONCLUSION:BCNU combined with Res exerts a synergistic effect that may prove useful for the treatment of colon cancer and to overcome drug resistance.

Pharmacological Study on Antitumor Activity of 5-Fluorouracil-1-Acetic Acid and Its Rare Earth Complexes

The antitumor activity of 5 fluorouracil 1 acetic acid(HFAA) and its lanthanide complexes(La(FAA) 3, Eu(FAA) 3) were studied. The results show that HFAA, La(FAA) 3 and Eu(FAA) 3 with the concentrations of 1 0×10 -5 ～1 0×10 -2 μg·ml -1 inhibit the colony formation of leukemia cells(L 1210 ) and the growth of transplanted tumor sarcoma 180(S 180 ), hepatic carcinoma(HEPA) and ehrlich ascites tumor(EC) as well. The maximum inhibitory rate of Eu(FAA) 3 for S 180 is 38 4%, that HFAA and La(FAA) 3 for EC are 22 4% and 43 4%, respectively. The life prolongation rate of Eu(FAA) 3 for HEPA bearing mice is as long as 284%.

Preparation,Crystal Structure,Thermal Decomposition and Explosive Properties of K_2(tza)_2(H_2O) (tza=Tetrazole-1-acetic Acid)

A new energetic compound based on the tetrazole-1-acetic acid （tza） and potassium（I） salt, K2（tza）2（H2O）, was synthesized and characterized by elemental analysis and FT-IR spectrum. Its crystal structure was determined by single-crystal X-ray diffraction analysis. The results show that the crystal belongs to the orthorhombic system, space group Pna21 with a = 1.11972（17） nm, b = 0.46647（7） nm, c = 2.5158（4） nm, V = 1.3140（3） nm3, K2C6H8N8O5, Mr = 350.40 g·mol-1, Dc = 1.771 g·cm^-3, μ（MoKα） = 0.759 mm^-1, F（000） = 712, Z = 4, R = 0.023 and wR = 0.0527 for 2961 observed reflections （I 〉 2σ（I））. The K（I） cation is six-coordinated with four O atoms from three carboxylate groups, one O atom from one H2O molecule and one N atom from tetrazolyl ring, in which each tza is coordinated in a tridentate chelating bridging coordination mode. The thermal decomposition mechanism of the title complex was studied by DSC and TG-DTG techniques. Under nitrogen atmosphere at a heating rate of 10 K·min-1, the thermal decomposition of the complex contains one main exothermic process between 191.7 and 243.8 ℃ in the DSC curve. Its combustion heat was mensurated by oxygen bomb calorimetry. The non-isothermal kinetics parameters were calculated by the Kissinger＇s method and Ozawa-Doyle＇s method, respectively. The sensitivity properties of K2（tza）2（H2O） were also determined with standard methods, which was very sensitive to flame.

Synthesis,Structure,and Surface Photo-electric Properties of a New Zn(Ⅱ)Coordination Complex Constructed from 2-(1H-benzotriazol-1-yl)acetic Acid and 1,10-Phenanthroline Ligands

A new binuclear Zn^Ⅱ coordination complex,Zn2（bta）（phen）2（Cl）3（1,Hbta = 2-（1Hbenzotriazol-1-yl）acetic acid and phen = 1,10-phenanthroline）,has been synthesized and characterized by single-crystal X-ray diffraction,IR spectroscopy,elemental,and photoluminescent analysis.Complex 1 crystallizes in triclinic system,space group P1 with a = 9.3040（19）,b = 10.694（2）,c =16.841（3） A°,α = 101.18（3）,β = 105.77（3）,γ = 91.72（3）°,V= 1575.8（5） A°3,C（32）H（22）Zn2Cl3N7O2,Mr =773.66,Dc = 1.631 g/cm^3,Z = 2,F（000） = 780,μ = 1.820 mm^-1,the final R = 0.1238 and wR =0.1131.X-ray diffraction analyses indicate that 1 displays two crystallographic independent Zn^Ⅱmetal centers with a distorted tetragonal pyramidal（ZnN4O） and a tetrahedral（ZnNCl3） geometries,respectively.The phen serves as a common N,N＇-bidentate ligand,and the bta^- as a unique N,O-bridged ligand in 1.In the crystal,1 forms a stable 3D supramolecular architecture by trifurcated hydrogen bonding C-H…C1 interactions and C-H…π,π…π stacking.1 showed photo-electric conversion properties.

Synthesis of Vanillin 1, 2-Propylene Glycol Acetal Catalyzed by H3PMo6W6O40·nH2O

Vanillin 1, 2-propylene glycol acetal was synthesized from vanillin and 1, 2-propylene glycol using H3PMo6W6O40·nH2O as catalyst, The factors influencing the synthesis were discussed and the better reaction conditions were found as follows： The amount of vanillin was 3.8 g, the molar ratio of vanillin was 1, 2-propylene glycol 1.0 to 2.4, the amount of catalyst was 1.6% in proportion to the total reacting materials, the volume ofcyclohexane as the water-carrying agent 4 mL, the refluxing time was 2 h at 88-96℃ and thus the product yield reached over 87%. The results show that the catalyst＇s activity is high and the reaction time is short.

醋酸亮丙瑞林对特发性中枢性性早熟女童血清IGF⁃1、IGFBP⁃3水平的影响

目的观察醋酸亮丙瑞林对特发性中枢性性早熟(ICPP)女童血清IGF⁃1、IGFBP⁃3的影响。方法选取2019年4月至2022年4月自贡市第四人民医院326例ICPP女童,随机分为观察组和对照组各163例,对照组予以醋酸甲地孕酮片,观察组加以醋酸亮丙瑞林微球皮下注射。比较两组临床疗效、BA/CA、成年预测终身高、乳房发育情况、血清性激素、B超检查结果、血清IGF⁃1、IGFBP⁃3及不良反应。结果治疗6个月后,观察组治疗总有效率高于对照组,差异有统计学意义(P<0.05);两组BA/CA均较治疗前减小,且观察组小于对照组,差异有统计学意义(P<0.05);两组成年预测终身高均较治疗前增加,且观察组高于对照组,差异有统计学意义(P<0.05);治疗后观察组乳房发育Tanner分期Ⅱ期、Ⅲ期占比低于对照组,差异有统计学意义(P<0.05);两组血清LH、E2、FSH水平均较治疗前降低,且观察组低于对照组,差异有统计学意义(P<0.05);两组子宫容积、卵巢容积、卵泡直径均较治疗前减小,且观察组小于对照组,差异有统计学意义(P<0.05);两组血清IGF⁃1、IGFBP⁃3水平均较治疗前降低,且观察组低于对照组,差异有统计学意义(P<0.05);两组不良反应总发生率比较差异无统计学意义(P>0.05)。结论醋酸亮丙瑞林治疗ICPP可下调性激素及IGF⁃1、IGFBP⁃3表达,抑制第二性征发育及骨成熟。

Improving Effect of Acetic Acid Bacteria (Gluconacetobacter hansenii GK-1) on sIgA and Physical Conditions in Healthy People: Double-Blinded Placebo-Controlled Study

It is known that the consumption of bacteria such as lactobacilli and bifidobacteria has beneficial effects on human immune function. Most of them are Gram-positive bacteria, and there are few reports on Gram-negative bacteria. In this study, we evaluated the effects of intake of Gluconacetobacter hansenii GK-1 (GK-1), Gram-negative acetic acid bacteria, for 12 weeks on physical condition and immune indices. We conducted a randomized, double-blind, placebo-controlled, parallel-group study in 100 healthy adults. The subjects were randomized into the GK-1 and the placebo groups. The diary-administered physical condition survey was conducted during the study period. The evaluation of salivary sIgA levels, NK-cell activity, and serum IFN-γ levels and quality of life survey was conducted before, in 6 weeks, and 12 weeks after the start of ingestion. Based on the physical condition survey, the cumulative onset-days of symptoms were significantly suppressed in the GK-1 group compared to the placebo group regarding the evaluation of 13 symptoms related to immunity, every 3 weeks. Additionally, salivary sIgA levels per hour were significantly increased in the GK-1 group compared with the placebo group at 6 and 12 weeks. Despite no significant differences in the NK-cell activity, serum IFN-γ levels or quality of life survey between the groups. Serum IFN-γ levels in the GK-1 group were significantly elevated at 12 weeks after the start of ingestion compared with those before ingestion. In conclusion, intake of GK-1 was shown to increase salivary sIgA levels and improve physical condition. This suggested that oral intake of GK-1 may help maintain the immune system.

COMPATIBILITY IN POLYMER BLENDS OF POLY (VINYL ACETATE) AND POLY (METHYL METHACRYLATE)STUDIED BY NMR

Compatibility of poly (vinyl acetate) (PVAc) with poly (methyl methacrylate) (PMMA) mixtures has been studied by using nuclear magnetic relaxation, differential scanning calorimeter and small-angle X-ray scattering techniques. The nuclear magnetic relaxation time T_1's were measured as a function of composition in blends of PMMA and PVAc prepared from chloroform solution. The results show that the system is miscible for casting from chloroform solution.