尿素分析色谱柱的国产化研制及应用

介绍尿素合成气分析的难点,通过实验室研制、试验及现场应用,满足实际分析指标,达到国产化替代要求。

S Zorb催化剂装置尿素分析方法改进及操作优化

针对S Zorb催化剂生产装置尾气处理单元实际情况,建立了新的吸收液尿素浓度分析方法。新建分析方法能够更准确地反映吸收液尿素真实浓度,并据此对处理单元进行了操作优化,二者结合较好地解决了含镍氨氮废水的平衡问题,对催化剂生产装置的连续正常生产、环保及节能增效具有重要的现实意义。

解吸水解废液中微量尿素分析方法讨论

中国石油宁夏石化公司的2套尿素装置先后采用甲醛法滴定分析、二乙酰一肟—氨基硫脲分光光度法、对二甲基氨基苯甲醛分光光度法进行解吸水解废液中微量尿素的分析。简述了上述3种分析方法的原理;对比了3种分析方法的优点和缺点;讨论了废液中的工艺介质对分析效果的影响程度。结果表明:①甲醛法滴定分析抗干扰能力强,是经典的分析方法;②若样品中不存在干扰物质,对二甲基氨基苯甲醛比色法是最快捷的分析方法;③若上述2种方法的分析数据产生争议,则采用二乙酰一肟分光光度法确认。

^(15)N-尿素发射光谱分析法检测幽门螺杆菌感染

目的 建立检测幽门螺杆菌感染的无损伤、无放射性方法———15N 尿素发射光谱分析法。方法 对 2 6例受检者用15N 尿素发射光谱分析法检测其幽门螺杆菌感染。结果 诊断特异性为 81% ,灵敏度为 89% ,阳性预测值为 84%。结论 该方法具有一定的实用意义。

尿素分析仪的校准方法探讨

提出尿素分析仪的一种校准方法。建立了以尿素标准物质校准仪器零点漂移、示值误差、示值重复性及稳定性的方法,并对仪器示值误差的不确定度进行了分析,相对扩展不确定度为0. 06mg/L(k=2)。该方法准确可靠,可实现尿素分析仪的校准和量值溯源。

尿素市场分析与预测

我国尿素市场价格在连续四年下跌后，2000年已跌过我国平均尿素生产成本，市场供应量严重供过于求。那么，今年乃至今后几年我国的尿素市场将会是什么样的形势呢?本文就此问题进行简要分析，供读者参考。

时间平均尿素浓度在预测血液透析间期心力衰竭中的价值

目的 :探讨时间平均尿素浓度 (Time- average Concentration of urea TACurea)在预测血液透析间期 (IHD)心力衰竭 (HF)中的临床价值。方法 :以 TACurea作为评价血液透析 (HD)充分性的客观指标 ,对 82例维持性血液透析(MHD)患者于 IHD发生 HF进行分析。结果 :MHD82例于 9986例次 IHD中发生 HF2 2 9例次 (2 .2 9% ) ,主要原因依次是 HD不充分、感染、高血压控制不良、贫血未纠正。HF组平均 TACurea为 (2 4 .6± 4 .5 ) mmol/ L,表明 TACurea≥ (2 4 .6± 4 .5 ) mmol/ L 易并发 MHD间期 HF。结论 :HD不充分是诱发 HD间期 HF的最主要因素 ,TACurea可以作为 MHD间期 HF的预测指标。

脑出血患者血糖、尿素、肌酐、白细胞水平变化与预后关系

【目的】探讨脑出血患者血糖 (Glu)、尿素 (Urea)、肌酐 (Crea)、白细胞 (WBC)水平变化与病情及预后关系。【方法】Glu、Urea、Crea分别采用葡萄糖氧化酶法、两点动力法、苦味酸法 ;白细胞计数用全自动血细胞分析仪完成。【结果】病人组与健康对照组比较 ,结果有显著性差异 (P <0 .0 1)。且Glu、Urea、Crea、WBC与病情正相关。【结论】动态检测患者Glu、Urea、Crea、WBC水平的变化 。

在线尿素清除率监测与尿素清除指数对血液透析充分性的评价及相关性分析

目的探讨在线尿素清除率监测（OCM）与尿素清除指数（Kt／V）在评价血液透析充分性中的价值及相关性分析。方法48例在成都军区昆明总医院血透中心行维持性血液透析的终末期肾衰患者，采用德国贝朗Dialog＋血透机自带OCM监测仪检测尿素清除指数（Kt／V），同时在透前、透后抽血，应用尿素动力学-室可变容积模型检测Kt／V计算值，并对OCM检测值和Kt／V计算值进行相关性分析；探讨OCM与尿素清除指数（Kt／V）在评价血液透析充分性中的作用。结果OMC与Kt／V比较差异无统计学意义（1．467±0．318v81．629±0．262，P〉0．05），但两者呈正相关（r=0．539，P〈0．01）。结论OCM检测值与应用尿素动力学-室可变容积模型计算的Kt／v值相近，二者关系密切相关，可以作为评价尿毒症血透患者血液透析充分性的一项较可靠指标。

Meta-analysis of the Use of ACEI for Inhibiting Albuminuria in Diabetic Patients

Aim To examine whether AER(albumin excretion rate) in normotensive diabeticpatients can be effectively inhibited by ACEI. Methods Literature on randomized controlled trials ofACEI for inhibiting AER in normotensive diabetic patients was searched. The electronic databasesretrieved were Medline (1980 ― 2003), Embase database (1980 ― 2000), Cochrane Library, CL( 1980 ―2004), CBMdisc( 1980 ― 2002), and IPA( 1980 ― 2002). Seven studies were chosen. Data werecombined by Revman 4.2. Results: The pooled effect of change in AER is - 56.31 μg·min^(-1)) [ -81.96, -30.66] (P<0.0001). According to the analysis of subgroups, the pooled effects of 1 - 5 yearsare - 11.97 μg·min^(-1)[-22.04, -1.89] (P = 0.02), -28.01 μg·min^(-1)[-34.50, -21.52](P<0.00001), -43.24 μg·min^(-1) [ -57.15, -29.32] (P< 0.00001), -61.65 μg·min^(-1)[77.77,-45.54] (P< 0.00001), and -98.41 μg·min^(-1)[-162.02,-34.79] (P = 0.002). Regarding progression toclinincal proteinuria as end-point, the pooled Peto OR =0.27 [0.18,0.40] (95% CI), P < 0.00001.According to the analysis of subgroups, the pooled effects of 2 and 5 years are Peto OR = 0.30[0.18,0.51] (P<0.00001) and Peto OR=0.25 [0.13, 0.50](P<0.0001). Publication bias is small.Conclusion In normotensive diabetic patients, ACEI inhibits AER effectively and reduces theprobability of progression of microalbuminuria to clinical proteinuria.

One-pot synthesis and structural characterization of urea-isobutyraldehyde-formaldehyde resin

Urea-isobutyraldehyde-formaldehyde (UIF) resin was synthesized from urea, isobutyraldehyde, and formaldehyde using sulfuric acid as a catalyst by one pot method. The effects of molar ratios of isobutyraldehyde to formaldehyde (n(I)/n(F)) and aldehyde to urea (n(A)/n(U)) on the yield, hydroxyl value (vs KOH) and softening point of the resin were investigated. The structure of the resin was characterized by FT-IR, 1H-NMR and 13C-NMR. The results show that when the molar ratio of urea to isobutyraldehyde to formaldehyde (n(U)/n(I)/n(F)) is 1.0/3.0/3.0, the yield UIF resin is 67.1%, and the softening point and hydroxyl value are 88 ℃ and 37 mg/g, respectively. The FT-IR, 1H-NMR and 13C-NMR results show that the lactam is formed by aminomethylation from urea, isobutyraldehyde, and formaldehyde.

A Preliminary Study on Natural Matrix Materials for Controlled Release Nitrogen Fertilizers

A controlled release N fertilizer was developed by the carrier method using natural polysaccharides (PS)and urea. The results showed that mixing of PS and urea led to significant control of urea release. When a cross-linker (boric acid or glutaraldehyde) was added, a better control effect was observed. During a 30 min leaching time the nitrogen release rate from the controlled release fertilizer was nearly constant, which was significantly different from normal urea. One of the controlled release mechanisms was related to space resistance from a large molecular structure. Infrared (IR) analysis indicated that interaction of PS with urea was through a hydrogen bond or a covalent bond. These bonds created an α-helix or high molecular network fertilizer carrier system, which was another reason for a controlled nutrient release. Pot experiment showed that nitrogen use efficiency could increase significantly with a carrier fertilizer.

A Combined Clinicopathologic Analysis of 658 Urothelial Carcinoma Cases of Urinary Bladder

Objective To study the clinicopathological features of patients with urothelial carcinoma of the urinary bladder (UCB), and analyze the association of clinicopathological characteristics with tumor recurrence and progression. Methods Altogether 658 UCB cases in Fudan University Shanghai Cancer Center were collected from January 2006 to December 2010. The histopathologic materials and the clinical records were reviewed. Univariate and multivariate analyses were preformed to detect the association. Results The mean age of the patients was 61.97±12.97 years (range, 20-90 years). Male to female ratio was about 5:1. A total of 517 cases (78.6%) were superficial at the time of diagnosis (stage Ta/T1). The mean follow-up period was 22.36±24.92 months. Twenty-five patients lacking follow-up information were excluded in calculating recurrence and progression rates, the recurrence rate was about 37.0% (234/633), and progression rate about 6.2% (39/633). Three variables (grade, tumor growth pattern, and pathological stage) were found to be significant risk factors for tumor progression in univariate and multivariate analyses (P<0.05). Conclusions Most of the newly diagnosed UCB cases may be superficial diseases. Grade, tumor growth pattern, and pathological stage are associated with tumor progression of UCB.

Electrodeposition Behavior of Nickel from a Low Temperature Urea-molten Salt

The electrodeposition behavior of nickel at glassy carbon(GC)and stainless steel(SS)electrodes in low temperature urea-acetamide-NaBr-KBr melt was investigated using cyclic voltammetry,chrono-amperometric current-time transients and scanning electron microscopy.Cyclic voltammograms and dimensionless chronoamperometric current-time transients analysis show that the electrodeposition of nickel is an irreversible process and proceeds via three-dimensional progressive nucleation with diffusion-controlled growth on both GC and SS substrates.Scanning electron microscopic analysis indicates the nickel deposits obtained on SS electrode are generally uniform,dense,and adherent to the substrate with rounded crystallites in the nanometer size regime.It is also found that the crystal structure of the electrodeposited nickel is independent on the deposition potential.The nickel deposits produced from the melt at higher cathodic potential exhibit larger grain size.

Validity and cost comparison of ^(14)carbon urea breath test for diagnosis of H Pylori in dyspeptic patients

AIM： To validate and compare the cost of microdose ^14C urea breath test （UBT） with histology and rapid urease test for the diagnosis of H Py/ori. METHODS： Ninety-four consecutive patients with dyspeptic symptoms undergoing gastroscopy were enrolled. Gastric biopsies were taken for histology and rapid urease test. UBT was performed after gastroscopy by microdose ^14 urea capsules. Sensitivity, specificity and accuracy of UBT were calculated and compared with histology and rapid urease test. Cost comparison of these tests was also performed. RESULTS： H pylori was diagnosed by histology and rapid urease test in 66 （70%） and 61 （65%） patients, while ^14C UBT detected infection in 63 （67%）. Accuracy of UBT was 93% in comparison with histology while its positive and negative predictive values were 97% and 84%, respectively. Comparison of ^14C UBT with rapid urease test gives an accuracy of 96%, with positive and negative predictive values of 95% and 97%, respectively. These results were highly reproducible with a Kappa test （P value 〈 0.001）. Cost of histology or rapid urease test with gastroscopy was 110 USD or 95 USD respectively while the cost of UBT was 15 USD.CONCLUSION： Microdose ^14C UBT was comparable to histology and rapid urease test. ^14C UBT is an economical, self sufficient and suitable test to diagnose active Hpylori infection in less developed countries.

Density Functional Theory Study of Infrared and Ultraviolet Spectra of Urea L-Malic Acid

Urea L-malic acid, a new second order nonlinear optical crystal, was studied using density functional theory （DFT）. PBEPBE/6-31＋G（d,p） method, the optimal method for comparing the results from the several DFT methods, was chosen to study the molecular structure. Infrared and ultraviolet-visible spectra were obtained and compared with experiments. The ultraviolet-visible spectrum was also analyzed by the molecular orbital population. The geometries, and the infrared and ultraviolet-visible spectra in water were studied using DFT methods in combination with the polarized continuum model to predict the perturbations by the solvent effect.

CHANGES OF PLASMA ENDOTHELIN AND ATRIAL NATRIURETIC PEPTIDE DURING THE ONSET AND AFTER TERMINATION OF PAROXYSMAL SUPRAVENTRICULAR TACHYCARDIA

Radioimmunoassays were used to measure the concentration changes of plasma endothelin(ET) and atrial natriuretic peptide(ANP) during the onset and after termination of paroxysmal supraventricular tachycardia(SVT). 30 cases were reviewed and compansons with 42 normal subjects were made. There are very significant differences(P<0.0001) in the concentration changes of both plasma ET and ANP during the onset and 30 minutes after the termination of SVT. During the onset period of SVT. the plasma ET and ANP were markedly elevated and 30 minutes after its termination they were lowered significantly, but their concentrations were still 2-fold higher than ihose of the control group. As the biological effects of ANP and ET are antagonistic to each other. their parallel elevation and lowering of plasma concentrations during and.after the termination of SVT reveal that these 2 hormones parucipate in the pathophysiological process of SVT. This phenomenon is possibly one of the homeostatic regulatory functions in the organism.

豫北地区血清胱抑素C、尿素的参考范围调查

目的拟建立血清胱抑素C、尿素的参考值和参考区间。方法对14 685名（年龄3~80岁）肾功能正常、无高血压、糖尿病、心血管病和慢性肾病家族史的健康体检者,采用经过有效性验证的检测系统对血清胱抑素C（cys-tatin C）、尿素（urea）进行检测。对结果的频数分布进行正态性检验,性别间结果差别的比较采用t检验。符合正态性分布时,用x-±1.96s为参考区间;不符合正态性分布时,取2.5%~97.5%为参考区间。结果血清胱抑素C、尿素结果的频数分布均为非正态性分布,男女之间结果差异有统计学意义（P〈0.05）。按照2.5%~97.5%确定二者的参考区间为：胱抑素C男0.25~1.04 mg/L,女0.24~1.02 mg/L;尿素男3.05~8.01 mmol/L,女2.88~7.79 mmol/L。二者的参考区间与文献提供的有一定的差异。结论应建立不同地区血清胱抑素C、尿素检测的参考值和参考区间。