小鼠皮肤切创愈合过程中caspase-3的表达及其活性

目的探讨皮肤切创愈合过程caspase-3的表达、激活情况及其活性的变化规律。方法建立小鼠皮肤切创模型后,应用比色法、Western blotting技术对小鼠皮肤切创愈合过程中不同时间段caspase-3的表达、激活情况及其活性进行研究。结果伤后不同时间的caspase-3活性倍增值、caspase-3酶原表达呈现时间规律性变化,并可见caspase-3的激活片段。结论caspase-3可能在皮肤损伤愈合过程中细胞的凋亡中发挥作用,caspase-3可以成为用于皮肤损伤时间推断的指标。     

DETECHIP®: A Sensor for Drugs of Abuse*

Abstract: The design and preliminary characterization of a novel sensor for drugs of abuse, DETECHIP^®, is described in this proof‐of‐concept note. Combining both colorimetric and fluorimetric assays, DETECHIP^® is suitable for lab and field use. More than a conventional spot test which provides a single “yes or no” answer, DETECHIP^® provides twenty responses for a more complete characterization of suspect material. This is accomplished by visually noting colorimetric and fluorescent changes of carefully selected dyes upon the addition of test analytes, including drugs of abuse, with respect to controls. Color and fluorescence changes are recorded numerically so that a 20 digit identification code can be constructed for comparison of test analytes and known compounds. DETECHIP^® is applicable to a variety of drugs, both plant‐derived and synthetic, addressing the need to use several different spot tests simultaneously for a single sample.     

Development of Rapid and Economical Colorimetric Screening Method for p‐Phenylenediamine in Variety of Biological Matrices and its Application to Eleven Fatal Cases of p‐Phenylenediamine Poisoning

A rapid colorimetric method for detection of p‐phenylenediamine (PPD) in various biological samples is developed. The o‐cresol test for acetaminophen detection has been modified to detect PPD in blood, urine, gastric contents, and liver. After precipitating protein with trichloroacetic acid solution (2 mL, 10% w/v), biological specimens were required to convert PPD metabolites to PPD by acid hydrolysis. Finally, o‐cresol solution (1 mL, 1% w/v), hydrogen peroxide (200 μL, 3%v/v), and concentrated ammonium hydroxide (0.5 mL) were added in the biological samples. The presence of PPD was indicated by formation of violet color which was turned to bluish green color within 10–15 min. The limit of detection was found to be 2 mg/L in blood, urine, and gastric contents and 2 mg/Kg in liver. This method is also free from any potential interference by p‐aminophenol, acetaminophen, and other amine drugs under test conditions. This method was successfully employed to thirteen fatal cases of PPD poisoning.     

Fingerprint reagents with dual action: color and fluorescence

We define "dual fingerprint reagents" as chemical formulations that produce with latent fingerprints in one stage impressions that are both colored and fluorescent. Solutions containing ninhydrin and group IIb metal salts appear to be true dual reagents. Application of these formulations to latent fingerprints on paper is as efficient as the two-step process beginning with ninhydrin and followed by treatment with metal salt. In the color mode, fingerprint detectability with the two ninhydrin-metal salt reagents (one with zinc chloride and the other with cadmium chloride) is comparable with that of ninhydrin itself, in spite of the difference in color. The sensitivity is significantly higher in the fluorescence mode. To view the latent impressions the exhibits are treated with ninhydrin-metal salt reagents and observed under white light illumination and under fluorescence conditions. Cooling to liquid nitrogen temperature enhances the fluorescence considerably. In the shorter wavelength domain, ninhydrin-metal salt reagents exhibit higher sensitivity than the recently reported dual reagent, genipin. The latter is advantageous, however, in the longer wavelength domain, on paper items with strong self-fluorescence, such as brown wrapping paper or paper printed with fluorescent ink. Upon reduction of the ninhydrin concentration 10-fold, ninhydrin-metal salt formulations become purely fluorogenic reagents; no color is noticed but the fluorescence is as intense as with concentrated solutions. Working at lower concentrations is an advantage from ecological and economical viewpoints.     

Structure elucidation of dyes that are formed in the colorimetric detection of the improvised explosive urea nitrate

Urea nitrate (uronium nitrate, UN) is a powerful, improvised explosive that can be easily made from urea and nitric acid. It is considered the most frequently used, illegal explosive in the Israeli arena, which is responsible for the loss of more than a hundred lives in terrorist incidents. Urea nitrate is a colorless, crystalline substance that looks very much like sugar. A sensitive color test for UN was developed recently. It is based on the formation of a red dye in the reaction between p-dimethylaminocinnamaldehyde and UN under neutral conditions. A similar reaction with p-dimethylaminobezaldehyde produces a yellow dye. The two dyes have been synthesized, and their structures determined by X-ray crystallography. Both dyes are protonated Schiff bases, prevailing in the crystal in a quinoid form. They are identical to the compounds, which are obtained in the colorimetric detection of urea with the same reagents, under strong acidic conditions, whose structures have been postulated in the literature, but never fully proved experimentally.     

酸性染料比色法测定宁心滴丸的含量

目的：采用酸性染料比色法测定宁心滴丸中的环维黄杨星D。方法：于410nm波长处检测显色后的氯仿提取液。结果：环维黄杨星D在0．9896－7．4420μg/ml范围内的直线回归方程为A＝0．04813＋0．06432C，相关系数γ＝0．9997，回收率为100．0％，RSD＝1．7％。结论：该方法简便、准确、无干扰，可用于宁心滴丸的质量控制。     

Chemical identification and optimization of the 4-aminophenol colorimetric test for the differentiation between hemp-type and marijuana-type cannabis plant samples

The 4- Aminophenol (4-AP) colorimetric test is a fast, easy-to-use, and cost-effective presumptive assay of cannabis plant material producing different chromophores with THC-rich cannabis (blue color) and with CBD-rich cannabis (pink color). The main drawback of the 4-AP test is a brief observation window where the color rapidly changes to black, limiting the utility of the test. We now report for the first time, the identification of the product chromophores between 4-AP and CBD/THC as well as propose an explanation and a solution for the color degradation of the chromophores. The identification of the chromophores is provided by spectroscopic (UV–Vis), chromatography, and mass spectrometry (TLC and LC-QToF-MS). Oxidation of excess 4-AP (Reagent A) in the presence of NaOH (Reagent B) produces the black color observed for the previously reported 4-AP tests and reported in the literature. The adjustment of reactants concentrations and volumes of 4-AP:THC/CBD to a 1:1 ratio significantly reduces the black oxidation by-product and increases the observation window up to 2 h instead of the previously reported 5–10 min. For the first time, mass spectrometry and chromatography confirmed that the reaction of THC and CBD with 4-AP produced chromophores with m/z (M + H) = 420, consistent with proposed indophenol structures. The TLC method developed confirmed the separation between CBD and THC chromophores. The specificity of the test is also reported, showing false positive results for the presence of THC (blue color) for samples of thyme and oregano. LDA and SIMCA models showed that the optimized 4-AP procedure performs better than the previously reported 4-AP color test.     

Applicability of two commercially available kits for forensic identification of saliva stains

The RSID-saliva test and the SALIgAE-saliva test are two recently developed forensic saliva detection kits. In this study, we compared the sensitivity and the specificity of the two test kits with the Phadebas amylase test by analyzing amylases from various sources including human, animals, plants, and micro-organism. The data demonstrate that the RSID-saliva test and the SALIgAE-saliva test offer higher sensitivity and specificity for the detection of saliva than the Phadebas amylase test. The detection limits of the RSID-saliva test, the SALIgAE-saliva test, and the Phadebas amylase test equate to 10, 4, and 1000 nL, respectively for human saliva. The RSID-saliva test and the SALIgAE-saliva test were further evaluated by analyzing semen, vaginal secretion, breast milk, blood, urine, sweat, and feces. The results of the two tests are in good agreement. The two tests reacted with urine, breast milk, and feces, but not with semen, vaginal secretion, blood, and sweat.