Human islet amyloid polypeptide oligomers stabilized and probed by MAS NMR

The capture and characterization of oligomers are extremely important in the studies of amyloid aggregation of proteins and peptides.Oligomers are critical intermediates that can impact the structures of amyloid fibrils.Moreover,it is widely accepted that oligomers are the most toxic species along the aggregation pathway[1e4].The studies of oligomers are believed to shed light on the molecular mechanism of amyloid fibrillation and probably the medical clues for related diseases.In vitro investigations of amyloid oligomers are challenging due to their transient and polymorphic nature[5].This is particularly evident in the case of human type-2 diabetes-associated islet amyloid polypeptide(hIAPP),which tends to rapidly form polymorphic fibrils within minutes[6].Notably,hIAPP demonstrates a higher propensity for rapid aggregation compared to other amyloid proteins such as a-synuclein[7].

Flame-retardant oligomeric electrolyte additive for self-extinguishing and highly-stable lithium-ion batteries:Beyond small molecules

Preparing both safe and high-performance lithium-ion batteries(LIBs) based on commonly used commercial electrolytes is highly desirable,yet challenging.To overcome the poor compatibility of conventional small-molecular flame-retardants as electrolyte additives for safe LIBs with graphite anodes,in this study,we propose and design a novel low-cost flame-retardant oligomer that achieves an accurate and complete reconciliation of fire safety and electrochemical performance in LIBs.Owing to the integration of phosphonate units and polyethylene glycol(PEG) chains,this oligomer,which is a phosphonatecontaining PEG-based oligomer(PPO),not only endows commercial electrolytes with excellent flame retardancy but also helps stabilize the electrodes and Li-ion migration.Specifically,adding 15 wt% of PPO can reduce 70% of the self-extinguishing time and 54% of total heat release for commercial electrolytes.Moreover,LiFePO_(4)/lithium and graphite/lithium cells as well as LiFePO_(4)/graphite pouch full cells exhibit good long-term cycling stability.

Mechanism Study of BF_(3)/n-Butanol-catalyzed 1-Decene Oligomerization Reaction

The active catalysts of the BF_(3)/n-C_(4)H_(9)OH-catalyzed 1-decene oligomerization reaction,as well as the distribution of the reaction products,was investigated by molecular simulation.The calculation results show that(BF_(3))_(2)·n-C_(4)H_(9)OH catalyzes the 1-decene oligomerization reaction with higher activity compared to BF_(3)·n-C_(4)H_(9)OH,which is the most catalytically active substance in the BF_(3)/n-C_(4)H_(9)OH catalyst system.The reaction energy barriers and heats of reaction of chain initiation,chain growth,and chain termination in BF_(3)/n-C_(4)H_(9)OH-catalyzed 1-decene oligomerization are calculated to reveal the product distribution.The calculation results show that the contents of the oligomerization reaction products in descending order are trimer,tetramer,pentamer,and dimer.The calculated results were consistent with the experimentally obtained product distribution.

Gefapixant,a Novel P2X3 Antagonist,Protects against Post Myocardial Infarction Cardiac Dysfunction and Remodeling Via Suppressing NLRP3 Inflammasome

Objective The ATP responsive P2 purinergic receptors can be subdivided into metabotropic P2X family and ionotropic P2Y family.Among these,P2X3 is a type of P2X receptor which is specifically expressed on nerves,especially on pre-ganglionic sensory fibers.This study investigates whether gefapixant possesses the potential of inhibiting cardiac sympathetic hypersensitivity to protect against cardiac remodeling in the context of myocardial infarction.Methods The Sprague-Dawley rats were divided randomly into three groups:sham group-myocardial infarction group,and myocardial infarction with gefapixant treatment group.Myocardial infarction was induced by left anterior descending branch ligation.The gefapixant solution was intraperitoneally injected each time per day for 7 days and the appropriate dosage of gefapixant was determined according to the results of hematoxylin-eosin(HE)staining and myocardial injury biomarkers.Conditions of cardiac function were assessed by echocardiograph and cardiac fibrosis was evaluated by Western blotting and immunofluorescence staining of collagen I and collagen III.The sympathetic innervation was detected by norepinephrine concentration(pg/mL),in-vivo electrophysiology,and typical sympathetic biomarkers.Inflammatory cell infiltration was shown from immunofluorescence staining and pro-inflammatory signaling pathway activation was checked by immunohistology,quantitative realtime PCR(qPCR)and Western blotting.Results It was found that gefapixant injection of 10 mg/kg per day had the highest dosage-efficacy ratio.Furthermore,gefapixant treatment improved cardiac pump function as shown by increased LVEF and LVFS,and decreased LVIDd and LVIDs.The expression levels of collagen I and collagen III,and TNF-αwere all decreased by P2X3 inhibition.Mechanistically,the decreased activation of nucleotide-binding and oligomerization domain-like receptors family pyrin-domain-containing 3(NLRP3)inflammasome and subsequent cleavage of caspase-1 which modulated interleukin-1β(IL-1β)and IL-18 level in heart after gefapixant treatment were associated with the suppressed cardiac inflammation.Conclusion It is suggested that P2X3 inhibition by gefapixant ameliorates post-infarct autonomic nervous imbalance,cardiac dysfunction,and remodeling possibly via inactivating NLRP3 inflammasome.

高师化学教育教学改革研究与实践

结合三年来承担世行贷款“师范教育发展项目”改革课题研究项目“培养适应多民族地区综合教育改革和经济建设需要的中学化学教师”的研究过程，就如何构建面向２１世纪的中学化学教师学科业务素质培养框架和化学教师文化知识框架、课程编制的理论基础采用结构主义课程论的考虑、教改的地方特色、在初中化学实验微型化中所做的工作、应当重视课外活动的作用等方面，报告我们所作的探讨。

酒精性肝病患者肝组织NLRP3炎症复合体基因水平检测及其意义

目的探讨核苷酸结合性寡聚区蛋白样受体(NLR)P3炎症复合体在酒精性肝病(ALD)发病中的作用。方法本研究获得酒精性肝炎(AH)12例、酒精性肝硬化(ALC)4例和健康人(HC)12例肝组织,采用RT-PCR法检测肝组织NLRP3、Caspase-1和IL-1βm RNA水平。采集ALD患者84例【AH20例、ALC48例(Child-Pugh A级19例、B级22例和C级7例)和重症酒精性肝炎(SAH)16例】和健康人40例血浆,采用ELISA法检测血浆IL-1β水平,采用Spearman秩相关分析血浆IL-1β水平与临床检验指标的相关性。结果 AH和ALC患者肝组织NLRP3 m RNA水平分别为(28.1±2.8)和(28.4±3.1),均显著高于HC组【(8.8±1.8),P<0.001】,Caspase-1m RNA水平分别为(18.8±1.2)和(24.6±1.8),均显著高于HC组【(15.1±1.0),P<0.05】,IL-1βm RNA水平分别为(17.0±2.9)和(16.3±4.4),均显著高于HC组【(7.0±1.1),P<0.01】;肝组织NLRP3 m RNA水平分别与IL-1βm RNA或Caspase-1 m RNA水平呈正相关(P<0.05);AH、ALC和SAH患者血浆IL-1β水平分别为(36.1±1.8)pg/m L、(28.0±1.6)pg/m L和(32.5±2.4)pg/m L,均显著高于HC组【(14.7±0.8)pg/m L,P<0.01】;不同Child-Pugh分级ALC患者IL-1β水平无显著性差异(P>0.05);ALD患者血浆IL-1β水平与ALT和AST/ALT比值呈正相关。结论 NLRP3炎症复合体主要组分及促炎细胞因子IL-1β在ALD患者肝组织和血浆水平升高,可能参与了ALD发病的炎症反应过程。

松树皮原花青素提取纯化及降血脂作用研究

[目的]研究松树皮原花青素的提取纯化方法和降血脂作用。[方法]分别采用浓度70%乙醇和大孔树脂对松树皮中原花青素进行了提取和纯化;以小白鼠为对象建立动物模型进一步研究了原花青素精提物的降血脂作用。[结果]经NKA大孔树脂纯化后的原花青素纯度达到40%左右;松树皮中原花青素具有降低小白鼠血清中甘油三酯(TG)、总胆固醇(TC)和低密度脂蛋白(LDL-C)含量的作用。[结论]松树皮原花青素提取物在一定程度上能起到降血脂的作用,为其在保健和医药等方面进一步开发利用提供科学依据。

Spontaneous bacterial peritonitis: The clinical challenge of a leaky gut and a cirrhotic liver

Spontaneous bacterial peritonitis(SBP) is a frequent, life-threatening bacterial infection in patients with liver cirrhosis and ascites. Portal hypertension leads to increased bacterial translocation from the intestine. Failure to eliminate invading pathogens due to immune defects associated with advanced liver disease on the background of genetic predisposition may result in SBP. The efficacy of antibiotic treatment and prophylaxis has declined due to the spread of multi-resistant bacteria. Patients with nosocomial SBP and with prior antibiotictreatment are at a particularly high risk for infection with resistant bacteria. Therefore, it is important to adapt empirical treatment to these risk factors and to the local resistance profile. Rifaximin, an oral, nonabsorbable antibiotic, has been proposed to prevent SBP, but may be useful only in a subset of patients. Since novel antibiotic classes are lacking, we have to develop prophylactic strategies which do not induce bacterial resistance. Farnesoid X receptor agonists may be a candidate, but so far, clinical studies are not available. New diagnostic tests which can be carried out quickly at the patient's site and provide additional prognostic information would be helpful. Furthermore, we need tools to predict antibiotic resistance in order to tailor first-line antibiotic treatment of spontaneous bacterial peritonitis to the individual patient and to reduce mortality.

Association between serum cartilage oligomeric matrix protein and coronary artery calcification in maintenance hemodialysis patients

Background Coronary artery calcification(CAC)is common in end-stage renal disease(ESRD)patients,and the extent of CAC is closely related to cardiovascular outcomes in ESRD patients.Cartilage oligomeric matrix protein(COMP),as a component of the vascular matrix,has been found to be an inhibitor of arterial calcification in basic studies.However,there is no clinical research on the correlation between COMP and CAC in maintenance hemodialysis(MHD)patients.The aim of this study was to explore the relationship between serum COMP levels and CAC and cardiovascular events in MHD patients.Methods Serum COMP levels were compared between 54 MHD patients and 66 healthy people.MHD patients were then divided into three groups according to the tertiles of the concentration of COMP level and were followed up for major adverse cardiac events(MACEs),which were defined as a combined end point of new onset angina pectoris,nonfatal myocardial infarction,heart failure,coronary artery revascularization,hospitalization due to angina pectoris and all-cause deaths.The CAC score was calculated based on computed tomography scans.Results The serum COMP level in MHD patients was significantly higher than that in the general population[984.23(248.43-1902.61)ng/mL vs.219.01(97.26-821.92)ng/mL,P<0.01].Serum COMP levels were positively correlated with CAC(r=0.313,P=0.021)and serum parathyroid hormone in MHD patients(r=0.359,P<0.01).Linear regression suggested that after adjusting for age,fasting blood glucose(Glu)and glycosylated hemoglobin(HbAlc),CAC score was an independent predictor in the final model for COMP level(β=0.424,t=3.130,P<0.01).The receiver operating characteristic(ROC)curve showed that COMP≥994 mg/mL had 68.0%sensitivity and 72.4%specificity for the prediction of severe CAC[area under the curve(AUC):0.674,P=0.030,95%CI:0.526-0.882].After a median follow-up of 16 months(8-24 months),there was no difference in the incidence rate of MACEs between the upper,middle and lower serum COMP groups.Conclusions Our study found that MHD patients have higher levels of circulating COMP than controls.The serum COMP level is positively correlated with CAC score and could be used as a biomarker of severe CAC in MHD patients.However,there is no obvious correlation between serum COMP levels and the incidence of cardiovascular events.

Cornel iridoid glycoside induces autophagy to protect against tau oligomer neurotoxicity induced by activation of glycogen synthase kinase-3β

Tau oligomers are the etiologic molecules of Alzheimer disease(AD), and correlate strongly with neuronal loss and exhibit neurotoxicity. Recent evidence indicates that small tau oligomers are the most relevant toxic aggregate species. The aim of the present study was to investigate the mechanisms of cornel iridoid glycoside(CIG) on tau oligomers and cognitive functions. We injected wortmannin and GF-109203 X(WM/GFX, 200 μmol·L-1 each) into the lateral ventricles to induce tau oligomer and memory impairment in rats. When oral y administered with CIG at 60 and 120 mg·kg-1 per day for 14 d, CIG decreased the escape latency in Morris water maze test. We also found that CIG restored the expression of presynaptic p-synapsin, synaptophysin, and postsynaptic density-95(PSD-95) decreased by WM/GFX in rat cortex. CIG reduced the accumulation of tau oligomers in the brain of WM/GFX rats and in cells transfected with wild type glycogen synthase kinase-3β(wt GSK-3β). In addition, CIG up-regulated the levels of ATG7, ATG12, Beclin-1, and LC3 II in vivo and in vitro, suggesting the restoration of autophagy function. These results suggest that CIG could ameliorate memory deficits and regulate memory-associated synaptic proteins through the clearance of tau oligomers accumulation. Moreover, CIG clears tau oligomers by restoring autophagy function.

Interleukin-6 and ratio of plasma interleukin-6/interleukin-10 as risk factors of symptomatic lumbar osteoarthritis

AIM To determine the role of cartilage oligomeric matrix protein(COMP), interleukin(IL)-6, IL-10 and ratio of IL-6/IL-10 as risk factors of symptomatic lumbar osteoarthritis(OA) in postmenopausal women with estrogen deficiency.METHODS Case-control study had been conducted in Sanglah General Hospital from October 2015 until March 2016. The blood samples were obtained and analyzed by enzyme-linked immunosorbent assay(ELISA).RESULTS From 44 pairs of samples which divided into 44 samples as case group and 44 samples as control group showed that high level of COMP in estrogen deficiency postmenopausal women were not at risk(OR = 0.7; 95%CI: 0.261-1.751; P = 0.393) for symptomatic lumbar OA(cut-off point 0.946). Estrogen deficiency in postmenopausal women with the high level of IL-6 had 2.7 times risk(OR = 2.7; 95%CI: 0.991-8.320; P = 0.033) for symptomatic lumbar OA from the low level of IL-6(cut-off point 2.264). At lower level of IL-10, there was no risk for symptomatic lumbar OA(OR = 0.6; 95%CI: 0.209-1.798; P = 0.345) than with the higher level of IL-10(cut-off point 6.049). While the high ratio of IL-6/IL-10 level in estrogen deficiency postmenopausal women gave 3.4 times risk(OR = 3.4; 95%CI: 1.204-11.787; P = 0.011)for symptomatic lumbar OA than the low ratio of IL-6/IL-10 level(cut-off point 0.364).CONCLUSION High ratio of IL-6/IL-10 plasma level was the highest risk factor for causing symptomatic lumbar OA in postmenopausal women with estrogen deficiency.

Inflammatory bowel disease:An archetype disorder of outer environment sensor systems

The pathogenesis of the two inflammatory bowel disease(IBD) phenotypes ulcerative colitis(UC) and Crohn' s disease(CD) has remained elusive,thus frustrating attempts at defining a cure.IBD often presents as a complex inflammatory process wherein colon lesions(UC) or widespread ulceration and fissure(CD) might be accompanied by ancillary extra-intestinal manifestations involving the eye,skin,joints or liver,but also by full-blown "autoimmune" disorders from psoriasis and multiple sclerosis to rheumatoid arthritis;attempts at unraveling a link or a hierarchical order in these entities have proven almost fruitless.More recently,the input of genetics has suggested that the IBDs might be multiorgan inflammatory processes,elicited by a large number of low-penetrance susceptibility genes,with environmental factors needed to induce full-blown disease.At a noteworthy exception to this rule,the description of the nucleotide-oligomerization domain(NOD) gene mutations in CD came at the beginning of the 2000s:the NOD-LRR are part of a highly conserved microbial sensor system which respond to bacterial peptidoglycans by mounting an inflammatory response.At least in Caucasian patients,the prevalently loss-of-function mutation of NOD permitted to unexpectedly define CD as an immune deficiency state,and upon its recent description in apparently unrelated disorders such as the Blau syndrome(a granulomatous pediatric syndrome),and perhaps in psoriasis and chronic obstructive pulmonary disorders,has contributed to revolutionize our view of IBD and CD in particular.The latter affection,together with psoriasis and chronic pulmonary disease can now be included into a newly identified category named "barrier organ disease",wherein a barrier organ is defined as a large mucosal or epithelial surface with an abundant metagenomic microbial population and an underneath reactive tissue,the whole structure being in contact with the outer environment and capable to react to it.Personalized treatments and empowerment of research across different disease phenotypes should be the advantages of this novel mindset.

Nucleotide oligomerization domain 2 contributes to the innate immune response in THCE cells stimulated by Aspergillus fumigatus conidia

·AIM:To investigate the expression of nucleotide oligomerization domain 2 (NOD2) in the immortalized human corneal epithelial cell line (THCE), and its role in the innate immune response triggered by inactive Aspergillus fumigatus (Af ) conidia.·METHODS:The normal THCE cells were investigated as controls. After incubation with inactive Af conidia for 0.5, 2, 4, 6, and 8 hours, THCE cells were harvested, mRNA expression of NOD2 and receptor interacting protein 2 (RIP2) was detected by RT-PCR. Intracellular proteins including NOD2, NF-κB and proinflammatory cytokines such as TNF-α, IL-8, IL-6 in the cell supernatant were analyzed by ELISA.·RESULTS:Our data indicate that NOD2 expressed in the normal THCE cells. After triggered by the inactive Af conidia, the expression of NOD2, RIP2 mRNA and the secretion of NOD2, NF-κB, TNF-α, IL-8, IL-6 both increased in a time-depended manner, and reached the peak point at 4, 6, 6, 4, 6, 6, 4 hours, respectively. And after pretreated with NOD2 neutralizing antibody, the expression of RIP2, NF-κB, TNF-α, IL-8 both decreased dramatically at the peak point, while the secretion of IL-6 changed little.·CONCLUSION:The results of this study suggest that NOD2 exists and expresses in the THCE cells, and contributes to the innate immune responses triggered by inactive Af conidia by induction of proinflammatory cytokines such as TNF-α and IL-8 through the NF-κB pathway.

Preparation and characterization of SMA/S-POSS hybrid membranes for direct methanol fuel cell applications

A novel sulfonated polyhedral oligomeric silsesquioxane(S-POSS) monomer was synthesized successfully in this article. S-POSS acted as a donor of sulfonic acid group and reacted with poly(styrene-co-maleic anhydride) (SMA). FT-IR spectroscopy confirmed the modification through introduction of peaks characteristic of ester linkages and carboxylic groups. The SMA/S-POSS hybrid membranes were fabricated from different S-POSS contents. The proton conductivity and methanol permeability of the hybrid membranes were studied with changing S-POSS content from 5wt.% to 30wt.%. It was found that the proton conductivity and the methanol permeability were dependent on the S-POSS content. Both of proton conductivity and methanol permeability properties improve with increasing S-POSS content. The proton conductivities of the hybrid membranes are in the range of 10-3-10-2 S·cm-1, and the range of methanol permeabilities was between 10-8 and 10-7 cm2·s-1. The membranes show good thermal properties characterized by thermogravimetric analysis (TGA).

SYNTHESIS, CHARACTERIZATION AND RING-OPENING POLYMERIZATION OF CYCLIC (ARYLENE PHOSPHONATE) OLIGOMERS

A series of cyclic (arylene phosphonate) oligomers were prepared by reaction of phenylphosphonic dichloride (PPD) with various bisphenols under pseudo-high dilution conditions via interfacial polycondensation. The yield of cyclic (arylene phosphonate) oligomers is over 85% by using hexadecyltrimethylammoniun bromide as phase transfer catalyst (PTC) at 0 "C . The structures of the cyclic oligomers were confirmed by a combination of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and IR analysis. These cyclic oligomers undergo facile ring-opening polymerization in the melt by using potassium 4,4’-biphenoxide as the initiator to give linear polyphosphonate. Free-radical ring-opening polymerization of cyclic(arylene phosphonate) oligomers containing sulfur linkages was also performed in the melt using 2,2’-dithiobis(benzothiazole) (DTB) as the initiator at 270 °C and the resulting polymer had a Mw, of 8 × 103 with a molecular weight distribution of 4. Ring-opening copolymerization of these cyclic oligomers with cyclic carbonate oligomers was also achieved. The average molecular weight of the resulting copolymer is higher than the corresponding homopolymer and the thermal stability of the copolymer is better than the corresponding homopolymer.

2-AMINOMETHYLPYRIDINE NICKEL(Ⅱ) COMPLEXES—SYNTHESIS,MOLECULAR STRUCTURE AND CATALYSIS OF ETHYLENE POLYMERIZATION

A series of new nickel(Ⅱ)complexes with 2-aminomethylpyridine ligands,(2-PyCH_2NHAr)_2NiBr_2(Ar=2,6- dimethylphenyl 2a;2,6-diisopropylphenyl 2b,2,6-difluorophenyl 2c),have been synthesized and used as catalyst precursors for ethylene polymerization in the presence of methylaluminoxane(MAO).The catalysts containing ortho-alkyl-substituents afford high molecular weight branched polyethylenes as well as a certain amount of oligomers.Enhancing the steric bulk of the alkyl substituent of the catalyst resulted...

Ultra-deep adsorptive removal of thiophenic sulfur compounds from FCC gasoline over the specific active sites of CeHY zeolite

Adsorption desulfurization performance of Na Y,HY and Ce HY zeolites is evaluated in a miniature fixedbed flow by model gasoline containing with thiophene,tetrahydrothiophene,2-methylthiophene,benzothiophene or mixed sulfur compounds.The structural properties of adsorbents are characterized by XRD,N2-adsorption and XPS techniques.Adsorption desulfurization mechanisms of these sulfur compounds over the specific active sites of adsorbents as a major focus of this work,have been systematically investigated by using in situ FT-IR spectroscopy with single and double probing molecules.Desulfurization experimental results show that the Ce HY adsorbent exhibits superior adsorption sulfur capacity at breakthrough point of zero sulfur for ultra-deep removal of each thiophenic sulfur compound,especially in the capture of aromatic 2-methylthiophene(about ca.28.6 mgS/gadsorbent).The results of in situ FT-IR with single probing molecule demonstrate an important finding that high oligomerization ability of thiophene or 2-methylthiophene on the CeHY can promote the breakthrough adsorption sulfur capacity,mainly resulting from the synergy between Br?nsted acid sites and Ce(III)hydroxylated species active sites located in the supercages of Ce HY.Meanwhile,the result of in situ FT-IR with double probing molecules further reveals the essence of oligomerization reactions of thiophene and 2-methylthiophene molecules on those specific active sites.By contrast,the oligomerization reaction of benzothiophene molecules on the active sites of Ce HY cannot occur due to the restriction of cavity size of supercages,but they can be adsorbed on the Br?nsted acid sites via protonation,and on Ce(III)hydroxylated species and extra-framework aluminum hydroxyls species via direct"S-M"bonding interaction.As to the tetrahydrothiophene,adsorption mechanism is similar to that of benzothiophene,except in the absence of protonation.The paper can provide a new design idea of specific adsorption active sites in excellent desulfurization adsorbents for elevating higher quality of FCC gasoline in the future.

SYNTHESIS AND CHARACTERIZATION OF A NOVEL BLUE LIGHT EMITTING ROD-COIL DIBLOCK OLIGOMER

Four new rod-coil diblock molecules, which had well-defined para-phenylene oligomers (PPP, from biphenyl to quinquephenyl) as rigid segments and poly(ethylene oxide) (PEO, Mw ca. 750) as flexible segments, were synthesized. The chemical structure and the number of repeating unit in PEO coil and PPP rod were characterized by 1H-NMR and MALDITOF mass spectrometry. The diblock oligomers showed good solubility in common organic solvents and aggregated in water as characterized by a blue shift in UV-vis absorption spectra, a red shift in emission spectra, quenching of the fluorescence and formation of the microfibrilla and fractal-like structures. The formation of different supramolecular structures meant that this effort might lead to commercial important highly organized functional materials.

STRUCTURAL STUDIES ON THE OLIGOMERS FROM THE POLYSACCHARIDE OF GRACILARIA TEXTORII (RHODOPHYTA) USING β-AGARASE AND 13C-NMR SPECTROSCOPY

The 60% ethanolic extract from Gracilaria textorii (Rhbdophyta) was degraded with B- agarase, and certain charged (sulfated) and neutral oligosaccharides were separated by using DEAE Sephadex A 25 and Bio- gel P6 , P2 chromatographic techniques . Some of the charged oligomers were verified to be neoagarotetraose - 63- sulfate ( DP2 ). neoagarohexaose- 63 】 65 - disulfate ( DP3 ) and neoagarooctaose- 63, 65, 67-trisulfate (DP4) by using 13C-and ’H-NMR spectroscopy . One neutral oligomer was assumed to be a mixture of methylated neoagarotetraoses (DP2 ) by 1H-NMR spectroscopy .These oligomers assigned by their chemical shifts may be used as the model compounds for the structural investigation of the agar- type sulfated polysaccharides using the B- agarase degradation method .

SYNTHESIS AND CHARACTERIZATION OF SILAZANE OLIGOMER CONTAINING 1,1,3,3,5,5-HEXAMETHYLCYCLOTRISILAZANE

A new silazane oligomer containing cyclotrisilazane was synthesized by KH-catalyzed dehydro-coupling reactionsbetween diphenylsilane and 1,1,3,3,5,5-hexamethylcyclotrisilazane （D3N）.