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1.
研究了新试剂4-(H酸偶氮)-1-苯基-3-甲基吡唑啉酮(HAPMP)与铁的显色反应,在pH7的NH4Ac缓冲介质中,CTMAB存在下,HAPMP与Fe(Ⅲ)生成3:1的紫色络合物.λmax=610nm,ε=7.68×104,铁含量在0~10μg/25mL内符合比尔定律,方法用于水样和镁合金中铁的测定.结果满意.  相似文献   

2.
胡秋芬  马莎  汤丹瑜  尹家元 《冶金分析》2001,21(4):18-19,11
研究了4-(8-羟基-3,6-萘二磺酸-1-偶氮)-1-苯基-3-甲基吡唑啉酮(HAPMP)与镁的显色反应,在pH10硼砂-氢氧化钠缓冲介质中,溴化十六烷基三甲基铵(CTMAB)存在下,镁与HAPMP生成2∶1络合物,λmax=560nm,ε=3.57×104.镁含量在0~10μg/25mL内符合比尔定律,方法用于钢铁样品中镁的测定,结果令人满意.  相似文献   

3.
研究了新显色剂5-(H-酸偶氮)-1-苯基-3-甲基吡唑啉酮(HAPMP)与铀(Ⅳ)的显色反应,在pH 4.0的HAc-NaAc缓冲介质中,新试剂与铀(Ⅳ)形成11的粉红色铬合物,最大吸收峰位于540 nm处,表观摩尔吸光系数为6.31×104,在25 mL溶液中铀质量在0~35 μg范围内符合比尔定律,方法用于合成样品中微量铀的测定,结果令人满意.  相似文献   

4.
研究了新显色剂 2 - (5-羧基 - 1 ,3,4-三氮唑偶氮 ) - 5-二乙氨基苯胺 (CTZAN)与Cu 的显色反应条件。结果表明 ,Cu 在 pH3 0的HAc -NaAc缓冲溶液中与CTZAN形成稳定的组成比为 1∶2的紫色络合物 ,λmax=565nm ,试剂的λmax=435nm ,对比度Δλ =1 30nm ,表观摩尔吸光系数ε =3 0 3× 1 0 4 ,Cu(Ⅱ )浓度在 0~ 0 8mg/L范围内服从比尔定律 ,所拟方法用于测定镁合金和铝合金标样中微量铜 ,加标回收率为 1 0 1 4%~ 1 0 4 0 % ,RSD(n =6) =1 4%~ 3 9% ,结果满意。  相似文献   

5.
研究了新试剂2-(5-溴-4-甲基-2-吡啶偶氮)-5-二甲氨基苯胺(5-Br-4-CH_3-PADMA)与镍(Ⅱ)的显色反应,建立了分光光度法测定镍的新方法。结果表明,在pH值为4.2~6.0的HAc-NaAc缓冲溶液中,在阴离子表面活性剂十二烷基硫酸钠(SDS)存在下,镍(Ⅱ)与5-Br-4-CH_3-PADMA形成稳定的组成比为1∶2的紫色配合物,其最大吸收波长位于567nm处。镍(Ⅱ)的质量浓度在0~0.40μg/mL范围内遵守比尔定律,校准曲线的线性相关系数r=0.999 2,表观摩尔吸光系数ε=1.22×10~5 L·mol~(-1)·cm~(-1)。以硫脲和氟化铵做掩蔽剂可消除Cu~(2+)、Fe~(3+)和Pd~(2+)等离子的干扰。方法用于铝合金中微量镍的测定,结果的相对标准偏差(RSD,n=6)为0.58%~0.98%,并与火焰原子吸收光谱法测定值一致。  相似文献   

6.
研究了新试剂1-(2,6-二氯-4-硝基苯)-3-(-4-硝基苯)-三氮烯(DCNPNPT)与钴(Ⅱ)显色反应的适宜条件.在表面活性剂Triton X-100存在下,Na2B4O7-NaOH缓冲液(pH.9.3)介质中,钴(Ⅱ)与DCNPNPT形成黄色络合物(12),其最大吸收波长为545nm,用双峰双波长法测定络合物的表观摩尔吸光系数ε=1.08×105,钴在0~240μg/L范围内符合比尔定律.此法已用于VB12针剂和矿样中微量钴(Ⅱ)的测定,结果满意.  相似文献   

7.
[目的]研究17-甲氧基-7-羟基-苯并呋喃查尔酮的分离方法及晶体结构.[方法]利用液液萃取、硅胶柱色谱、重结晶等方法进行目标物的分离,并通过IR、NMR、ESI-MS、X-射线单晶衍射等手段鉴定晶体结构.[结果]晶体结构分析结果表明,该化合物为单斜晶系,空间群P2(1)/c,晶胞主要参数:a=10.881 3(16)nm,b=9.795 4(14)nm,c=13.347 3(19)nm,V=1 382.2(3)nm<'3>,Z=4,Dc=1.414mg/m<'3>,F(000)=616,μ=0.100/mm.[结论]从玉郎伞[Millettia Pulchra Kurz var.Laxior(Dunn)Z.Wei]的60%(体积分数)乙醇水提取物中首次分离并鉴定了17-甲氧基-7-羟基-苯并呋喃查尔酮.  相似文献   

8.
探讨了2-(5-碘-2-吡啶偶氮)-5-二甲氨基苯胺(5-I-PADMA)与钯(Ⅱ)的显色反应。实验表明,在0.6 mol/L高氯酸介质中,5-I-PADMA与钯(Ⅱ) 反应形成摩尔比为1∶1的蓝色稳定络合物,该络合物最大吸收峰位于613 nm处。钯(Ⅱ)含量在0~0.6 μg/mL范围内符合比尔定律,线性回归方程为△A=0.828 4 ρ(μg/mL)- 0.001 6,相关系数r=0.999 9,表观摩尔吸光系数为8.82 × 104 L·mol-1·cm-1。方法应用于钯分子筛和矿样中钯的测定,结果与原子吸收光谱法一致,相对标准偏差(n=6)为1.2%~1.4%。  相似文献   

9.
研究了新合成的 1-( 2-羟基-3,5- 二硝基苯基 )- 3-[4 -(苯基偶氮 )苯基 ] - 三氮烯 (HDNPAPT)试剂与镍的显色反应。在Na2 B4 O7 NaOH介质中 (pH10. 0~ 10. 6)及乳化剂OP存在下 ,镍与HDNPAPT形成稳定的 1:1红色络合物 ,λmax=5 45nm ,表观摩尔吸光系数ε545=1.45× 10 5,镍浓度在 0~ 8μg/2 5mL范围内符合比尔定律。拟定的新方法已应用于铝合金中微量镍的测定 ,结果满意  相似文献   

10.
本文首次报道了十四种以荧光“四分组效应”反映热力学稳定性“四分组效应”的镧系 4- ( 3,5-二苯基 -2 -吡唑啉 - 1 - )苯磺酸配合物 ,〔Ln( Dpbs) 2 · ( H2 O) 4 〕Dpbs· n H2 O,其中 Dpbs=4- ( 3,5-二苯基 - 2 -吡唑啉 - 1 - )苯磺酸根离子 ,n=0或 2的合成及以元素分析、电导、溶解性、X-射线粉末衍射、热天平、红外、紫外和可见光及荧光光谱等数据对配合物结构表征和性质的研究。  相似文献   

11.
12.
The N-nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a potent lung carcinogen present in tobacco and tobacco smoke. Carbonyl reduction, alpha-carbon hydroxylation (activation) and N-oxidation of the pyridyl ring (detoxification) are the three main pathways of metabolism of NNK. In this study, metabolism of NNK was studied with lung and liver microsomes from F344 rats, Syrian golden hamsters and pigs and cloned flavin-containing monooxygenases (FMOs) from human and rabbit liver. Thermal inactivation at 45 degrees C for 2 min reduced FMO S-oxygenating activity but did not affect N-oxidation of NNK, leading to the conclusion that FMOs are not implicated in the detoxification of NNK. Detoxification of NNK was not increased by n-octylamine or by incubation at pH 8.4, supporting the conclusion that FMOs are not involved in the metabolism of NNK. SKF-525A (1 mM) significantly reduced N-oxidation and alpha-carbon hydroxylation, suggesting that these two pathways were catalyzed by cytochromes P450. Metabolism of NNK was lower with lung microsomes than with liver microsomes. Inhibition of metabolism of NNK by SKF-525A was also observed with rat lung microsomes, leading to the conclusion that cytochromes P450 are involved in pulmonary metabolism of NNK. Cloned FMOs did not metabolize NNK. In conclusion, cytochromes P450 rather than FMOs are involved in N-oxidation of NNK. The high capacity of hamster liver microsomes to activate NNK does not correlate with the resistance of this tissue to NNK-induced hepatocarcinogenesis.  相似文献   

13.
The tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a potent pancreas carcinogen in rats. The biliary excretion of NNK was therefore studied in anesthetized female Sprague-Dawley rats following i.p. administration of 0.7 mumol/kg [carbonyl-14C]NNK. The concentration of radioactivity peaked within 30 min and decreased thereafter exponentially. Cumulative excretion of radioactivity reached a plateau at 6-9% of the total dose. HPLC analysis revealed the presence of 4-hydroxy-4-(3-pyridyl)butyric acid (hydroxy acid), 4-oxo-4-(3-pyridyl)-butyric acid (keto acid), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butyl beta-D-glucopyranosiduronic acid (NNAL Glu), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and NNK. NNAL Glu was the major metabolite contributing 34 +/- 4% of total radioactivity in bile at 30 min and 58 +/- 4% at 5 h. The percentage of acidic metabolites remained constant at approximately 20%. In contrast, the percentage of NNK and NNAL decreased within the first 2 h to < 5% and < 10% respectively. The elimination kinetics of NNK and its metabolites fitted into a one-compartment model with a half-life of 37 min for NNK, 52 min for NNAL and 110 min for NNAL Glu and acidic metabolites. In three rats dosed with 240 mumol/kg NNK i.p., the concentration of radioactivity peaked after 1-2 h and decreased very slowly thereafter. After 5-8 h a total of 12-17% of the dose has been excreted in the bile with no indication of a plateau. At all time points NNAL Glu was the major metabolite contributing up to 95% of total radioactivity in bile. The percentage of acidic metabolites was < 5% throughout the experiment. Whereas NNK contributed one-third of the radioactivity at 30 min and decreased rapidly, the percentage of NNAL in bile remained rather constant at approximately 5-10%. In conclusion, the detection of NNK, NNAL and NNAL Glu gives support to the hypothesis that tobacco-specific carcinogens could reach the pancreas retrograde from the bile, especially at high NNK concentrations.  相似文献   

14.
Synthesis of (R)-(-)- and (S)-(+)-synadenol (1a and 2a, 95-96% ee) is described. Racemic synadenol (1a + 2a) was deaminated with adenosine deaminase to give (R)-(-)-synadenol (1a) and (S)-(+)-hypoxanthine derivative 5. Acetylation of the latter compound gave acetate 6. Reaction with N, N-dimethylchloromethyleneammonium chloride led to 6-chloropurine derivative 7. Ammonolysis furnished (S)-(+)-synadenol (2a). Absolute configuration of 1a was established by two methods: (i) synthesis from (R)-methylenecyclopropanecarboxylic acid (8) and (ii) X-ray diffraction of a single crystal of (-)-synadenol hydrochloride. Racemic methylenecyclopropanecarboxylic acid (10) was resolved by a modification of the described procedure. The R-enantiomer 8 was converted to ethyl ester 13 which was brominated to give vicinal dibromides 14. Reduction with diisobutylaluminum hydride then furnished alcohol 15 which was acetylated to the corresponding acetate 16. Alkylation-elimination procedure of adenine with 16 yielded acetates 17 and 18. Deprotection with ammonia afforded a mixture of Z- and E-isomers 1a and 19 of the R-configuration. Comparison with products 1a and 2a by chiral HPLC established the R-configuration of (-)-synadenol (1a). These results were confirmed by X-ray diffraction of a single crystal of (-)-synadenol hydrochloride. The latter forms a pseudosymmetric dimer with adenine-adenine base pairing in the lattice with the nucleobase in an anti-like conformation. Enantiomers 1a and 2a exhibit varied enantioselectivity toward different viruses. Both enantiomers are equipotent against human cytomegalovirus (HCMV) and varicella zoster virus (VZV). The S-enantiomer 2a is somewhat more effective than R-enantiomer 1a in herpes simplex virus 1 and 2 (HSV-1 and HSV-2) assays. By contrast, enantioselectivity of antiviral effect is reversed in Epstein-Barr virus (EBV) and human immunodeficiency virus type 1 (HIV-1) assays where the R-enantiomer 1a is preferred. In these assays, the S-enantiomer 2a is less effective (EBV) or devoid of activity (HIV-1).  相似文献   

15.
PURPOSE: Assessment of sustained voluntary contraction of the external sphincter is helpful in evaluating the patient who has a defecation disorder on presentation. A new index of external sphincter function is described. METHOD: A prospective registry of patients referred for computerized anal manometry using standard protocols was reviewed. Patients were grouped by primary symptoms; those with overlapping complaints were excluded. The rate of fatigue, defined as the change in stationary squeeze over a 40-second period of voluntary contraction, was calculated by linear regression analysis. Fatigue rate index, a calculated measure of time necessary for the external sphincter to become completely fatigued, was determined to permit comparison of external sphincter fatigue in patients with different complaints. RESULTS: Twenty-six healthy volunteers (15 women; mean age, 45 years), 33 patients with a primary complaint of anal seepage (13 women; mean age, 53 years), 75 patients with gross incontinence (61 women; mean age, 53 years), and 49 patients with severe constipation (41 women; mean age, 45 years) were evaluated. Mean resting and squeeze pressures were 55 mmHg and 107 mmHg for volunteers, 37 mmHg and 97 mmHg for patients with seepage, 30 mmHg and 49 mmHg for incontinent patients, and 56 mmHg and 93 mmHg for constipated patients. Pudendal neuropathy, as evidenced by a prolonged pudendal nerve terminal motor latency (> 2.4 ms), was identified in 13 percent of volunteers, 32 percent of patients with seepage, 54 percent of incontinent patients, and 38 percent of constipated patients. Mean fatigue rate index was 3.3 minutes for volunteers, 2.3 minutes for seepage patients, 1.5 minutes for incontinent patients, and 2.8 minutes for constipated patients. Compared with volunteers and patients with seepage, the incontinent patients had a significantly shorter fatigue rate index (P < 0.05; Student's t-test), which was independent of the variations in resting pressure (P < 0.05; two-way analysis of variance). CONCLUSION: The external anal sphincter is normally subject to fatigue. Patients with worsening degrees of incontinence have a predictably lower fatigue rate index. Fatigue rate index is a simple measure of external sphincter integrity, which may be used in assessment of sphincter function and future treatment protocols.  相似文献   

16.
Structural modifications requiring novel synthetic chemistry were made to the morpholine acetal human neurokinin-1 (hNK-1) receptor antagonist 4, and this resulted in the discovery of 2-(R)-(1-(R)-3, 5-bis(trifluoromethyl)phenylethoxy)-3-(S)-(4-fluoro)phenyl-4-(3-ox o-1 ,2,4-triazol-5-yl)methyl morpholine (17). This modified compound is a potent, long-acting hNK-1 receptor antagonist as evidenced by its ability to displace [125I]Substance P from hNK-1 receptors stably expressed in CHO cells (IC50 = 0.09 +/- 0.06 nM) and by the measurement of the rates of association (k1 = 2.8 +/- 1.1 x 10(8) M-1 min-1) and dissociation (k-1 = 0.0054 +/- 0.003 min-1) of 17 from hNK-1 expressed in Sf9 membranes which yields Kd = 19 +/- 12 pM and a t1/2 for receptor occupancy equal to 154 +/- 75 min. Inflammation in the guinea pig induced by a resiniferatoxin challenge (with NK-1 receptor activation mediating the subsequent increase in vascular permeability) is inhibited in a dose-dependent manner by the oral preadmininstration of 17 (IC50 (1 h) = 0.008 mg/kg; IC90 (24 h) = 1.8 mg/kg), indicating that this compound has good oral bioavailbility and peripheral duration of action. Central hNK-1 receptor stimulation is also inhibited by the systemic preadministration of 17 as shown by its ability to block an NK-1 agonist-induced foot tapping response in gerbils (IC50 (4 h) = 0.04 +/- 0.006 mg/kg; IC50 (24 h) = 0.33 +/- 0.017 mg/kg) and by its antiemetic actions in the ferret against cisplatin challenge. The activity of 17 at extended time points in these preclinical animal models sets it apart from earlier morpholine antagonists (such as 4), and the piperidine antagonists 2 and 3 and could prove to be an advantage in the treatment of chronic disorders related to the actions of Substance P. In part on the basis of these data, 17 has been identified as a potential clinical candidate for the treatment of peripheral pain, migraine, chemotherapy-induced emesis, and various psychiatric disorders.  相似文献   

17.
"Cardiomyopathy", a term formerly used for heart muscle disease of unknown aetiology, is at present applied to all myocardial diseases other than coronary-heart disease. This definition includes many different forms of metabolic disorders of heart muscle. Four manifestations of metabolic myocardial disease, differing in their aetiology and pathogenesis are distinguished: (1) "transport" myocardosis, (2) "arthrocytotic" myocardosis, (3) myocardia, and (4) idiopathic cardiomyopathy. They are differentiated by combined morphological and quantitative mineral examination. "Transport" myocardosis is the most common form and its particular aetiology can be further specified. Cause of death in patients with metabolic disorders often remains undiscovered even at autopsy. Combination of histological and quantitative mineral analysis of myocardium can further define the particular form.  相似文献   

18.
The effects of administration of low doses of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), a tobacco-specific nitrosamine, were investigated in hamsters treated with N-nitrosobis(2-oxopropyl)amine (BOP). Female Syrian golden hamsters were given a single sc injection of BOP at a dose of 10 mg/kg and then administered 2 or 5 ppm NNAL in their drinking water for 52 wk. Additional groups of animals received the BOP injection alone, or only the 2 or 5 ppm NNAL treatments as BOP-negative controls. At wk 53 of the experiment, all surviving animals were killed and the development of proliferative lesions was assessed histopathologically. The total incidence of combined carcinomatous and dysplastic lesions of the exocrine pancreas was significantly higher (P < 0.05) in the BOP/NNAL 5 ppm group than in the BOP alone group, although there was no statistically significant influence of NNAL on the development of either pancreatic adenocarcinomas or dysplastic lesions viewed singly. The treatments with NNAL alone did not induce any proliferative lesions of the exocrine pancreas. No significant intergroup differences were found in either incidence or multiplicity of islet cell proliferative lesions. Immunohistochemical examination of islet cell proliferative lesions (hyperplasias and adenomas) found in the BOP-treated animals showed no significant differences in pancreatic hormone production between NNAL-treated and -untreated groups. The NNAL treatment did not exert any influence on lung, liver or kidney tumorigenesis. Thus, the results suggest that NNAL enhances BOP-induced exocrine but not endocrine pancreatic tumorigenesis in hamsters when given in the post-initiation phase.  相似文献   

19.
The sulfone derivative of the non-steroidal anti-inflammatory drug (NSAID), sulindac, has been reported to inhibit mammary and colon tumor formation in rodent models of chemically-induced carcinogenesis. Unlike its parent compound, this metabolite lacks cyclo-oxygenase inhibitory activity. A tumor induction protocol, consisting of NNK administration in the drinking water over several weeks to model chronic human exposure, was used to test whether the sulfone (called FGN-1) could inhibit the formation of primary lung tumors in mice. A total of 150 female, AIN76A-fed, A/J mice received 9 mg of NNK each. Concentrations of FGN-1 that had been previously determined not to affect body weight gain were added to the food at levels of 0, 250, 500 and 750 mg/kg of diet (30 mice/group) starting 2 weeks before NNK administration and continuing for 22 weeks. At that time pleural surface tumors were counted. Tumor incidence decreased significantly from 96 % in the control diet and 93% in the 250 FGN-1 mg/kg diet to 63 and 67% in the 500 and 750 mg FGN-1/kg diet groups, respectively (P < 0.001 by chi-square analysis). Lung tumor multiplicity decreased from 18.1+/-3 tumors/ mouse (mean+/-SEM, control diet) to 12.3+/-3 (250), 5.3+/-1 (500) and 2.1+/-1 (750) (P < 0.0005 by post hoc ANOVA). In previous studies using this carcinogenesis protocol, the maximum tolerated dose of sulindac inhibited lung tumor multiplicity by no more than 50% with no effect on incidence. This dose-dependent reduction in tumorigenesis by a non-toxic dose of FGN-1 indicates a strong chemopreventive activity against experimental induction of lung carcinogenesis. The greater potency of the sulfone over sulindac and its lack of toxic side effects because of its inability to affect cyclo-oxygenase activity suggests that clinical testing in individuals at high risk for lung cancer should be considered.  相似文献   

20.
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