Redemitting BODIPY boronic acid fluorescent sensors for detection of lactate

Two redemitting BODIPY boronic acid pinacolate derivatives, sensors 1 and 2 were shown to act as excellent and highly selective lactate detectors at physiological pH (7.4), where the formed sensor-lactate complexes exhibited a significant emission and absorption increase. Since hyperlactataemia ([l-lac] > 6.5 mM) is a common complication in intensive care units, there is need for easy, on-line monitoring of lactate levels in patients. Semi-invasive monitoring via a lactate electrode or optic fiber would be attractive. This may beneficially replace existing lactate detection methods requiring a high degree of instrumentation. Sensors 1 and 2 can detect lactate without interference from biological important monosaccharides, such as d-glucose, d-fructose and d-mannose.     

Simple and cost-effective determination of ciprofloxacin hydrochloride by electrical micro-titration

By employing an electrical micro-titration system, in which a capacitively coupled contactless conductivity detector(C4D) was used to monitor the reaction process in real time, herein a novel method for determining ciprofloxacin hydrochloride(CIPHCl) was developed for the first time. Mode 1: Standard CIPHCl solutions at different concentrations were loaded into reaction cells, respectively, and were titrated with standard Ag+. Upon the titration, the formation of a precipitate alters the number of ions in the solution, raising the change of conductivity, which was monitored by a special C~4 D to construct a titration curve. The endpoint of the titration was located from the peak of the curve. Between the elapsed time and the initial concentration of titrand, a linear relationship was established over the range of2.0–8.0 mmol/L. Mode 2: Standard Fe~(3+) took the place of Ag~+, and was used as titrant to recognize ciprofloxacin contributed to the formation of complexation, which also resulting a change of solution conductivity. Under optimized conditions, a working range of 1.0–5.0 mmol/L CIPHCl was found. Because the reaction solutions were isolated from the working electrodes, this pioneer work shows significant simplicity and cost-effectiveness, by eliminating the requirements for detector exchange/renewal between different measurements, and by involving no auxiliary chemicals. Both of the two approaches were applied successfully to determine CIPHCl in tablet samples. And the results were in good agreement with those obtained by reference method.     

GC FPD method for the simultaneous speciation of butyltin and phenyltin compounds in waters

A method is described for the simultaneous determination of nanogram amounts of mono-, di- and tri-butyltin compounds in water. The procedure is based on the conversion of tin compounds to volatile species by Grignard pentylation and analysis using GC with flame photometric detection (GC FPD). The ionic compounds are extracted from diluted acidified (HBr) aqueous solutions by using a pentane-tropolone solution. The extracted organotin compounds are pentylated by a Grignard reagent and purified on a Fluorisil column before analysis by GC FPD. The detection limits are 20 ng dm^?3 for butyltin compounds and 50 ng dm^?3 for phenyltin compounds. Recoveries from spiking experiments in tap-water and natural seawater matrices, in which no organotin compounds were detected, were greater than 90% for most of the alkyltin compounds.     

GaAs IMSM光电探测器及其与FET的单片集成研究

采用S.I.GaAs衬底上MBE生长的两层结构外延材料制作了IMSM-PD并与采用离子注入材料制作的IMSM-PD的特性进行了比较,结果表明采用MBE材料的器件特性较优,在5V偏置电压下暗电流小于1nA。已将IMSM-PD与MESFET放大电路进行了单片集成构成光接收器。     

射线检测数字实时成像的不一致性研究

在基于PaxScan4030平板探测器技术的射线检测中,输出图像的像质除受系统噪声的影响外,同时还受探测器固有的光电响应不一致性的影响。通过对影响平板探测器输出图像质量的分析,建立了探测器响应不一致性校正模型。在用常规叠加方法去除噪声的同时,利用校正因子对采集图像进行实时校正,以改善系统性能,提高成像质量。通过实验数据分析和对校正前后输出图像的比较,验证了此方法的可行性,从而为射线检测提供了一种有效的校正方法。     

气相色谱热离子化检测器铯源的研究

报道了气相色谱热离子化检测器铯源的制作工艺及响应特性,并对各种影响因素进行了探讨。     

Fission cross section and fragment angular distribution in gold fission induced by 55 MeV alpha particles using solid state nuclear track detectors

The angular distribution of fission fragments in alpha induced fission has been studied at an incident energy of 55 MeV in¹⁹⁷Au target. The relative differential fission cross sections were measured at different angles between 10° and 170° and the resulting angular distributions fitted by least squares method with Legendre polynomials. In the present work, a correction for the self-scattering and self-absorption of fission fragments in the target itself was applied and a target of 3 mg/cm² was used to get good statistics. The anisotropy for 55 MeV alpha induced fission of gold was 2·83±0·43 and the fission cross section calculated by integrating the measured angular distributions over all the solid angles was 5·2±1.0 mb, confirming the value of 4·0±0·05 mb reported by Burnettet al but contrary to the high value of 10±3 mb reported by Ralarosyet al.     

Effect of gamma energy, temperature and shelf life on the response of gamma and BD-100R neutron bubble detectors

The use of commercially available bubble detectors for gamma and neutron detection has been reported by several groups. We have carried out systematic investigations to study the response of gamma bubble detector as a function of energy, the effect of waiting time on sensitivity of BD-100R neutron bubble detector and the effect of shelf life on both types of bubble detectors. Our results show that the response of the gamma bubble detector is energy dependent. Waiting time of up to 260 hours for BD-100R neutron detector has no significant effect. Both the detectors have a limited shelf life. These factors must be taken into account while using these detectors.     

基于功率谱分析的指纹实时识别系统

把实时获取指纹的装置与功率谱分析系统结合起来，实现完整的指纹实时识别系统．从实验上研究了相干光源和非相干光源获取指纹的两种情况．实验表明，用非相干光源获取指纹的情况具有较好识别效果．     

Development of high resolution silicon surface barrier detectors

Fabrication methods for silicon surface barrier detectors and their correlated properties which result in the production of high resolution (< 20 keV) devices have been studied. The techniques for fabrication and testing of the detectors currently employed at our Centre are presented. An FWHM of 14keV for 5·486 MeV²⁴¹Am α has been achieved. Our results are therefore comparable with the best in the world.