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1

Phenolphthalein—Pink Tornado Demonstration  

NASA Astrophysics Data System (ADS)

The phenolphthalein-pink tornado demonstration utilizes the vortex generated by a spinning magnetic stirring bar in a 1 L graduated cylinder containing 0.01 M HCl to demonstrate Le Châtelier's principle as it applies to the phenolphthalein equilibrium in water H 2 In + 2H 2 O 2H 2 O + + In 2 - where H 2 In is phenophthalein. The addition of 3-4 drops of phenolphthalein indicator solution followed immediately by 3-4 drops of 50% (w/w) NaOH to the vortex of the HCl solution results in a shift to the right in the equilibrium owing to the reaction of OH - + H 3 O + to form water. This shift is accompanied by the vortex becoming visible by the appearance of a pinkish-red color caused by an increase in In 2- concentration within the localized region of the vortex. The demonstration also provides one an excellent opportunity to discuss the topics of limiting reagent and reagent in excess. Some insight regarding the extent to which uniform mixing is achieved when using a magnetic stirrer is also provided. Included is a note from the Feature Editor, Ed Vitz.

Prall, Bruce R.

2008-04-01

2

Estrogenic effects of phenolphthalein on human breast cancer cells in vitro  

Microsoft Academic Search

Summary There is a structural similarity between phenolphthalein and the triphenylethylenes which are known to interact with the estrogen receptor of human breast tissue. Phenolphthalein (10 µM) competed with estrogen for binding to MCF-7 human breast cancer cells in tissue culture and induced the synthesis of the progesterone receptor. The antiestrogen 4-hydroxytamoxifen blocked progesterone receptor induction both by estradiol and

Peter Marcus Ravdin; Marc van Beurden; V. Craig Jordan

1987-01-01

3

Phenolphthalein induces centrosome amplification and tubulin depolymerization in vitro.  

PubMed

Aneuploidy is a major cause of human reproductive failure and plays a large role in cancer. Phenolphthalein (PHT) induces tumors in rodents but its primary mechanism does not seem to be DNA damage. In heterozygous TSG-p53(®) mice, PHT induces lymphomas and also micronuclei (MN), many containing kinetochores (K), implying chromosome loss (aneuploidy). The induction of aneuploidy would be compatible with the loss of the normal p53 gene seen in the lymphomas. In this study, we confirm PHT's aneugenicity and determine the aneugenic mechanism of PHT by combining traditional genetic toxicology assays with image and flow cytometry methods. The data revealed that PHT induces tubulin polymerization abnormalities and deregulates the centrosome duplication cycle causing centrosome amplification. We also show that one of the consequences of these events is apoptosis. PMID:23677914

Heard, Pamela L; Rubitski, Elizabeth E; Spellman, Richard A; Schuler, Maik J

2013-05-16

4

Effect of thermodynamic history on secondary relaxation in glassy phenolphthalein-dimethyl-ether  

Microsoft Academic Search

We present a study of the intermediate secondary relaxation process of phenolphthalein-dimethyl-ether. Though this process is intramolecular in nature, it reveals pronounced pressure dependence. Moreover, its relaxation frequency and intensity exhibit pronounced dependence on the thermal history followed during vitrification. These results suggest that the nonequilibrium nature of the glassy state influences this secondary relaxation principally through the dependence on

D. Prevosto; S. Capaccioli; M. Lucchesi; P. A. Rolla; M. Paluch; S. Pawlus

2006-01-01

5

Metabolic comparison of radiolabeled aniline- and phenol-phthaleins with 131I  

Microsoft Academic Search

The metabolic comparison of aniline- and phenol-phthaleins radiolabeled with 131I (131I-APH and 131I-PPH, respectively) has been investigated in this study. To compare the metabolic behavior of these phthaleins and their glucuronide conjugates radiolabeled with 131I, scintigraphic and biodistributional techniques were applied using male Albino rabbits. The results obtained have shown that these compounds were successfully radioiodinated with a radioiodination yield

U?ur Avc?ba??; Nesibe Avc?ba??; Turan Ünak; Perihan Ünak; Fazilet Zümrüt Müftüler; Yeliz Y?ld?r?m; Haluk Dinçalp; Fikriye Gül Gümü?er; Ebru Rük?en Dursun

2008-01-01

6

Phenolphthalein induces thymic lymphomas accompanied by loss of the p53 wild type allele in heterozygous p53-deficient (+/-) mice.  

PubMed

Epidemiology studies have indicated that many human cancers are influenced by environmental factors. Genetically altered mouse model systems offer us the opportunity to study the interaction of chemicals with genetic predisposition to cancer. Using the heterozygous p53-deficient (+/-) mouse, an animal model carrying one wild type p53 gene and one p53 null allele, we studied the effects of phenolphthalein on tumor induction and p53 gene alterations. Earlier studies showed that phenolphthalein caused carcinogenic effects in Fisher 344 rats and B6C3F1 mice after a 2-yr dosing period (Dunnick and Hailey, Cancer Res. 56: 4922-4926, 1996). The p53 (+/-) mice received phenolphthalein in the feed at concentrations of 200, 375, 750, 3,000, or 12,000 ppm (approximately 43, 84, 174, 689, or 2,375 mg/kg body weight/day or 129, 252, 522, 2,867, or 7,128 mg/m2 body surface area/day) for up to 6 mo. A target organ cancer site that accumulated p53 protein in the B6C3F1 mouse (i.e., thymic lymphoma) was also a target site for cancer in the p53 (+/-) mouse. In the p53 (+/-) mouse, treatment-related atypical hyperplasia and malignant lymphoma of thymic origin were seen in the control and dosed groups at a combined incidence of 0, 5, 5, 25, 100, and 95%, respectively. Twenty-one of the thymic lymphomas were examined for p53 gene changes, and all showed loss of the p53 wild type allele. Chemical-induced ovarian tumors in the B6C3F1 mouse showed no evidence for p53 protein accumulation and did not occur in the p53 (+/-) mouse. The p53-deficient (+/-) mouse model responded to phenolphthalein treatment with a carcinogenic response in the thymus after only 4 mo of dosing. This carcinogenic response took 2 yr to develop in the conventional B6C3F1 mouse bioassay. The p53-deficient (+/-) mouse is an important model for identifying a carcinogenic response after short-term (< 6 mo) exposures. Our studies show that exposure to phenolphthalein combined with a genetic predisposition to cancer can potentiate the carcinogenic process and cause p53 gene alterations, a gene alteration found in many human cancers. PMID:9437796

Dunnick, J K; Hardisty, J F; Herbert, R A; Seely, J C; Furedi-Machacek, E M; Foley, J F; Lacks, G D; Stasiewicz, S; French, J E

7

Toxicology and Carcinogenesis Studies of Phenolphthalein (CAS No. 77-09-8) in F344/N Rats and B6C3F1 Mice (Feed Studies).  

National Technical Information Service (NTIS)

Under the conditions of these 2-year feed studies, there was clear evidence of carcinogenic activity of phenolphthalein in male F344/N rats based on markedly increased incidences of benign pheochromocytomas of the adrenal medulla and of renal tubule adeno...

1996-01-01

8

Surface modification of phenolphthalein poly(ether sulfone) ultrafiltration membranes by blending with acrylonitrile-based copolymer containing ionic groups for imparting surface electrical properties  

Microsoft Academic Search

Asymmetric ultrafiltration membranes were fabricated from the blends of phenolphthalein polyethersulfone (PES-C) and acrylonitrile copolymers containing charged groups, poly(acrylonitrile-co-acrylamido methylpropane sulfonic acid) (PAN-co-AMPS). From the surface analysis by XPS and ATR-FTIR, it was found that the charged groups tend to accumulate onto the membrane surface. This result indicated that membrane surface modification for imparting surface electrical properties could be carried

Meng Wang; Li-Guang Wu; Xing-Cun Zheng; Jian-Xiong Mo; Cong-Jie Gao

2006-01-01

9

Phenolphthalein-Pink Tornado Demonstration  

ERIC Educational Resources Information Center

|The titration of HCl with NaOH has traditionally been used to introduce beginning chemistry students to the concepts of acid-base chemistry and stoichiometry. The demonstration described in this article utilizes this reaction as a means of providing students an opportunity to observe the dynamic motion associated with a swirling vortex and its…

Prall, Bruce R.

2008-01-01

10

Preparation of thermoresponsive Fe3O4/P(acrylic acid-methyl methacrylate-N-isopropylacrylamide) magnetic composite microspheres with controlled shell thickness and its releasing property for phenolphthalein.  

PubMed

In this work, Fe3O4/P(acrylic acid-methyl methacrylate-N-isopropylacrylamide) (Fe3O4/P(AA-MMA-NIPAm)) thermoresponsive magnetic composite microspheres have been prepared by controlled radical polymerization in the presence of 1,1-diphenylethene (DPE). The shell thickness of thermosensitive polymer (PNIPAm), which was on the surface of the microspheres, can be controlled by using DPE method. The morphology and thermosensitive properties of the composite microspheres, polymerization mechanism of the shell were characterized by TEM, FTIR, VSM, Laser Particle Sizer, TGA, NMR, and GPC. The microspheres with narrow particle size distribution show high saturation magnetization and superparamagnetism. The thermosensitive properties of the composite microspheres can be adjusted indirectly via controlling the addition amount of monomer (NIPAm) in the second step during controlled radical polymerization. Phenolphthalein was chosen as a model drug to investigate drug release behavior of the thermoresponsive magnetic composite microspheres with different shell thickness. Controlled drug release testing reveals that the release behavior depends on the thickness of polymer on the surface of the microspheres. PMID:23511014

Zhang, Baoliang; Zhang, Hepeng; Fan, Xinlong; Li, Xiangjie; Yin, Dezhong; Zhang, Qiuyu

2013-02-24

11

Kinetics of the Fading of Phenolphthalein in Alkaline Solution.  

ERIC Educational Resources Information Center

Described is an experiment which illustrates pseudo-first-order kinetics in the fading of a common indicator in an alkaline solution. Included are background information, details of materials used, laboratory procedures, and sample results. (CW)

Nicholson, Lois

1989-01-01

12

21 CFR 310.545 - Drug products containing certain active ingredients offered over-the-counter (OTC) for certain uses.  

Code of Federal Regulations, 2010 CFR

...1999. Danthron Phenolphthalein (C) Stimulant laxatives âApproved as of November 5, 2002. Aloe ingredients (aloe, aloe extract, aloe flower extract) Cascara sagrada ingredients (casanthranol, cascara fluidextract...

2009-04-01

13

21 CFR 310.545 - Drug products containing certain active ingredients offered over-the-counter (OTC) for certain uses.  

Code of Federal Regulations, 2010 CFR

...1999. Danthron Phenolphthalein (C) Stimulant laxatives âApproved as of November 5, 2002. Aloe ingredients (aloe, aloe extract, aloe flower extract) Cascara sagrada ingredients (casanthranol, cascara fluidextract...

2010-04-01

14

A radioanalytical technique for measurement of beta-glucuronidase activities  

Microsoft Academic Search

Summary  Phenolphthalein-glucuronide is a commonly used glucuronide conjugate for beta-glucuronidase measurements. The quantity of\\u000a phenolphthalein liberated by beta-glucuronidase is measured spectrophotometrically. The detection limit of the quantity of\\u000a phenolphthalein using spectrophotometry is a few ?g. In this study, a new radioanalytical technique for the measurement of\\u000a beta-glucuronidase was applied which is 106times more sensitive than the spectrophotometric technique. Radioiodinated phenolphthalein-glucuronide and

T. Ünak; U. Avciba?i; Y. Yildirim

2005-01-01

15

The Best Enzyme Investigation Ever? Probably.  

ERIC Educational Resources Information Center

|Uses alkaline phosphate to remove the phosphate group from phenolphthalein diphosphate. Discusses problems which include the interference of ambient light and temperature variation. Provides detailed information about the apparatus and the experimental procedure. (ASK)|

Cooper, Phil

2000-01-01

16

Public Notificaiton: “DaiDaiHuaJiaoNang” Contains ...  

Center for Drug Evaluation (CDER)

... Phenolphthalein is a solution used in chemical experiments and a suspected ... or. (301) 796-3400. druginfo@fda.hhs.gov. Human Drug Information ... More results from www.fda.gov/drugs/resourcesforyou/consumers

17

Synthesis of Polyether-Modified Polycarbonate Elastomers.  

National Technical Information Service (NTIS)

Block copolymers based on polyether polyols and compounds related to the bisphenol structure were synthesized by copolycondensation with phosgene. Elastomers were obtained from the copolycondensation of hydroxy terminated polyethers with phenolphthalein, ...

R. A. Faoro

1969-01-01

18

"Mud" + "Blood"--A Very Colorful Demonstration.  

ERIC Educational Resources Information Center

Describes a demonstration in which a bloodred-colored solution of hydrogen peroxide, sodium hydroxide, and phenolphthalein indicator is added to a mud-colored solution of potassium permanganate, hydrated manganous chloride, and sulfuric acid. The mixture turns clear when added together. Draws parallels between the demonstration and the Old…

Hambly, Gordon

1998-01-01

19

Demonstrating Diffusion  

ERIC Educational Resources Information Center

|Two demonstrations are described. Materials and instructions for demonstrating movement of molecules into cytoplasm using agar blocks, phenolphthalein, and sodium hydroxide are given. A simple method for demonstrating that the rate of diffusion of a gas is inversely proportional to its molecular weight is also presented. (AJ)|

Foy, Barry G.

1977-01-01

20

A Laboratory Experiment on the Dynamics of the Land and Sea Breeze  

Microsoft Academic Search

The land and sea breeze (LSB) circulation was simulated in a laboratory using a temperature controlled water tank. Flow visualization by tellurium and phenolphthalein and velocity measurement by laser-Doppler velocimeter were carried out in addition to temperature measurements. from similarity considerations, the simulated flow pattern was shown to have good correspondence with that in the atmosphere. It was shown that

Shigeki Mitsumoto; Hiromasa Ueda; Hiroyuki Ozoe

1983-01-01

21

27 CFR 21.102 - Caustic soda, liquid.  

Code of Federal Regulations, 2013 CFR

...with distilled water at room temperature. Transfer a 25 ml aliquot of the solution to a titration flask, add 10 ml of 1 percent barium chloride solution, 0.2 ml of 1 percent phenolphthalein indicator, and 50 ml of distilled water. Titrate with...

2013-04-01

22

"Mud" + "Blood"--A Very Colorful Demonstration.  

ERIC Educational Resources Information Center

|Describes a demonstration in which a bloodred-colored solution of hydrogen peroxide, sodium hydroxide, and phenolphthalein indicator is added to a mud-colored solution of potassium permanganate, hydrated manganous chloride, and sulfuric acid. The mixture turns clear when added together. Draws parallels between the demonstration and the Old…

Hambly, Gordon

1998-01-01

23

Effect of butylated hydroxyanisole on hepatic glucuronidation and biliary excretion of drugs in mice.  

PubMed

Inhibition of glucuronidation by depletion of UDP-glucuronic acid from liver impairs the hepatobiliary transport of glucuronidated xenobiotics. However, it is not known if enhancement of hepatic glucuronidation increases the biliary excretion of these compounds. Therefore, the effect of treatment with butylated hydroxyanisole (BHA), which increases hepatic glucuronidation capacity, on the biliary excretion of compounds undergoing glucuronidation was studied in mice. BHA-feeding (1% for 10 days) increased hepatic UDP-glucuronic acid content by 240% and enhanced hepatic UDP-glucuronosyltransferase activities (expressed per kg body weight) toward valproic acid, phenolphthalein, iopanoic acid and bilirubin 220, 180, 120 and 60%, respectively. BHA treatment did not influence the biliary excretion of unmetabolized cholephils, phenol-3,6-dibromphthalein disulphonate and phenolphthalein glucuronide, but enhanced that of phenolphthalein (+108%), iopanoic acid (+63%) and bilirubin (+33%) as glucuronides. However, these increases were apparent only in the initial phase of excretion. In contrast, BHA markedly decreased (-43%) the biliary excretion of valproic acid glucuronides. Simultaneously, BHA increased the urinary excretion of the glucuronides of phenolphthalein (+48%), iopanoic acid (+450%) and valproic acid (+150%). A shift in the distribution of iopanoic acid and valproic acid and metabolites from liver to kidney was also apparent in BHA-fed mice. Thus, enhanced glucuronidation does not facilitate the biliary excretion of all glucuronidated compounds and only transiently increases others. It is likely that this phenomenon is the result of the glucuronides readily entering the plasma and being excreted by the kidney. PMID:2900301

Gregus, Z; Klaassen, C D

1988-04-01

24

21 CFR 155.120 - Canned green beans and canned wax beans.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 false Canned green beans and canned wax beans. 155.120 Section 155.120...wash to remove phenolphthalein. Dry the screen containing the fibrous...the quality of the canned green beans or canned wax beans falls...

2009-04-01

25

21 CFR 155.120 - Canned green beans and canned wax beans.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Canned green beans and canned wax beans. 155.120 Section 155.120...wash to remove phenolphthalein. Dry the screen containing the fibrous...the quality of the canned green beans or canned wax beans falls...

2013-04-01

26

21 CFR 155.120 - Canned green beans and canned wax beans.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Canned green beans and canned wax beans. 155.120 Section 155.120...wash to remove phenolphthalein. Dry the screen containing the fibrous...the quality of the canned green beans or canned wax beans falls...

2010-04-01

27

Net alkalinity and net acidity 1: Theoretical considerations  

Microsoft Academic Search

Net acidity and net alkalinity are widely used, poorly defined, and commonly misunderstood parameters for the characterization of mine drainage. The authors explain theoretical expressions of 3 types of alkalinity (caustic, phenolphthalein, and total) and acidity (mineral, CO2, and total). Except for rarely-invoked negative alkalinity, theoretically defined total alkalinity is closely analogous to measured alkalinity and presents few practical interpretation

Carl S. Kirby; Charles A. Cravotta

2005-01-01

28

A CRITICAL REVIEW OF TECHNIQUES USED TO ASSESS CARBONATION IN LIME MORTARS  

Microsoft Academic Search

The carbonation process in high-calcium lime mortars, as well as the chemical, physical and environmental issues involved, are outlined. Literature on carbonation measurement is reviewed and the following techniques are examined: Scanning Electron Microscopy (SEM), Optical Microscopy (OM), Powder X-Ray Diffraction (XRD), Raman Spectroscopy, Differential Thermogravimetric Analysis (DTA), Phenolphthalein staining, Gravimetry, Velocity of the Propagation of Ultrasound Pulses, Elemental Analysis,

R. M. H. Lawrence

29

A Novel Method for Removing Sulfur Compounds from Light Oil by Molecular Recognition with ?-Cyclodextrin  

Microsoft Academic Search

Studies have been carried out aimed at recognizing ?-cyclodextrin as including sulfur compounds by competitive inclusion using phenolphthalein as a spectral probe. 1-Propanethiol was chosen as a model sulfur compound and the obtained results indicated that ?-CD could include 1-propanethiol and remove it from light oil. The time and the temperature of inclusion and the mass content of ?-CD in

Yan Sun; Daohong Xia; Yuzhi Xiang

2008-01-01

30

Molecular Models of Indicators  

NSDL National Science Digital Library

The article by Nicholas C. Thomas and Stephen Faulk on "Colorful Chemical Fountains" (1) reminds us that color—the colors of acid–base indicators or of metal complexes—is responsible for many of us developing an interest in chemistry. The featured molecules this month are the acid and base forms of three common indicators–phenolphthalein, methyl orange, and methyl red. These three substances display interesting structural features as the pH-induced transformation from one form to another takes place in three different ways. In the case of phenolphthalein, the lactam ring is cleaved on deprotonation to produce a carboxyl group with the concomitant removal of a proton from a phenolic group. In methyl orange, one of the nitrogen atoms is protonated in the acid form, and that proton is lost in the base form. In methyl red, a carboxylic acid function is deprotonated. There are many other interesting aspects of acid–base indicators. Since most plants and fruits contain pigments that show a color change in some pH range, it is difficult to state with any degree of certainty when these changes were first put to use in a systematic fashion. The Spanish alchemist Arnaldus de Villa Nova (Arnold of Villanova) is purported to have used litmus in the early 14th century. In general systematic use of indicators is traced to the latter half of the nineteenth century with the development of the three synthetic indicators described above. Many students will be familiar with the use of phenolphthalein to identify blood—often shown on the various forensic chemistry TV dramas by dropping some solution on a cotton swab that has been used to pick up some of the sample in question. If the swab turns red we frequently hear "It's blood". The reality of using phenolphthalein in this way is more complicated. The test is presumptive for the presence of blood, but not conclusive. It is not an acid–base reaction but rather, in the presence of hydrogen peroxide, relies on hemoglobin to catalyze the oxidation of phenolphthalein. An interesting assignment for students in a high-school or non-majors course would be to have them explore the details of this Kastle–Meyers test to see just what is involved in the correct application of the test, and what factors complicate the process. For example, would tomato juice infused with asparagus juice give a positive Kastle–Meyers test? Historically phenolphthalein was used in a variety of laxatives. Recently that usage has been discontinued due to concern about the carcinogenic nature of the substance. A review of the history of the controversy surrounding the use of phenolphthalein in laxatives would make a good research paper at the high-school level. Lastly, students with some practice building structures and performing calculations might wish to explore the structures of two other forms of phenolphthalein—one found in very acidic solutions, having an orange color, and one found in very basic solutions that is colorless.

31

Witches' Potion Demonstration  

NSDL National Science Digital Library

In this chemistry demonstration, learners will discover that phenolphthalein is an acid/base indicator. One learner will read a poem about four witches making a potion. Four learners will act out the parts, adding chemicals and water to different beakers (with adult supervision). Learners will enjoy the poem as the indicators react with the substances and change color. This is a fun chemistry demonstration to use during Halloween.

House, The S.

2013-05-15

32

Carbonation and its effects in reinforced concrete  

SciTech Connect

Carbonation is the result of interaction of carbon dioxide (CO{sub 2}) gas in the atmosphere with the alkaline hydroxides in the concrete. CO{sub 2} diffuses through the concrete and rate of movement of the carbonation front roughly follows Fick's law of diffusion. Carbonation depth can be measured by exposing fresh concrete and spraying it with phenolphthalein indicator solution. An example of the test on a reinforced concrete mullion is given.

Broomfield, J.P.

2000-01-01

33

Which Powder is It?  

NSDL National Science Digital Library

In this chemistry challenge, learners identify an unknown white powder by comparing it with common household powders. Learners first explore what happens when baking soda, baking powder, and washing soda are mixed with water, vinegar, and PHTH (the indicator phenolphthalein mixed with alcohol and water). Learners then work to identify the unknown based on how it reacts with the known solutions. This is a simplified form of "qualitative analysis," which was historically an important approach chemists used for identifying unknown samples.

Sciencenter

2012-06-26

34

Structure in turbulent mixing layers and wakes using a chemical reaction  

Microsoft Academic Search

Plane turbulent mixing between two streams of water which contained dilute chemical reactants was studied in a new blow-down water tunnel. In a diffusion-limited reaction, a pH indicator, phenolphthalein, in one stream mixed and reacted with a base, sodium hydroxide, in the other stream to form a visible reaction product. The product was found to exist, as expected, in concentrated

R. Breidenthal

1981-01-01

35

Synthesis and characterization of poly(arylene ether ketone) (co)polymers containing sulfonate groups  

Microsoft Academic Search

Poly(arylene ether ketone)s containing sulfonate groups were synthesized by aromatic nucleophilic polycondensation of 4,4?-difluorobenzophenone (DFK), sodium 2,5-dihydroxybenzensulfonate (SHQ) and bisphenols. Only low-molecular weight oligomer was obtained when hydroquinone (HQ) was employed as comonomer, while copolymerization of DFK, SHQ, and phenolphthalein (PL) proceeded quantitatively to high-molecular weight (reduced viscosities above 0.68dL\\/g) in dimethylsulfoxide at 175°C in presence of anhydrous potassium carbonate.

Feng Wang; Tianlu Chen; Jiping Xu; Tianxi Liu; Hongyan Jiang; Yinhua Qi; Shengzhou Liu; Xinyu Li

2006-01-01

36

Qualitative Analysis of Fourteen White Solids and Two Mixtures Using Household Chemicals  

Microsoft Academic Search

This is a revised and expanded version of a previously published qualitative analysis scheme for the identification of 11 white solids using materials readily available in drugstores, supermarkets, or variety stores. Phenolphthalein has been eliminated because the FDA banned its use in over-the-counter laxatives; instead, tests for pH are conducted using red cabbage indicator. Once commonly used by diabetics to

Maria Oliver-Hoyo; Deedee Allen; Sally Solomon; Bryan Brook; Justine Ciraolo; Shawn Daly; Leia Jackson

2001-01-01

37

Mutagenic activation of biliary metabolites of benzo(a)pyrene by  -glucuronidase-positive bacteria in human faeces  

Microsoft Academic Search

Summary. Human faeces hydrolysed synthetic P-D-glucuronides of both p-nitro- phenol and phenolphthalein. The origin of this activity in faeces was localised in the bacterial pellet fraction after centrifugation. Ninety-seven bacterial strains with P-glucuronidase activity isolated from fresh human faeces were identified as species of Bacteroides, Peptostreptococcus, Fusobacterium, Propionibacterium, Clostridium, Eubacteriurn and Bijidobacterium. They were classified into two groups according to

M. NANNO; H. MOROTOMI; H. TAKAYAMA; T. KUROSHIMA; R. TANAKA; M. MUTAI

1986-01-01

38

Rapid screening of illicit additives in weight loss dietary supplements with desorption corona beam ionisation (DCBI) mass spectrometry  

Microsoft Academic Search

Desorption corona beam ionisation (DCBI), the relatively novel ambient mass spectrometry (MS) technique, was utilised to screen for illicit additives in weight-loss food. The five usually abused chemicals – fenfluramine, N-di-desmethyl sibutramine, N-mono-desmethyl sibutramine, sibutramine and phenolphthalein – were detected with the proposed DCBI-MS method. Fast single-sample and high-throughput analysis was demonstrated. Semi-quantification was accomplished based on peak areas in

H. Wang; Y. Wu; Y. Zhao; W. Sun; L. Ding; B. Guo; B. Chen

2012-01-01

39

Rapid screening of illicit additives in weight loss dietary supplements with desorption corona beam ionization (DCBI) mass spectrometry  

Microsoft Academic Search

Desorption corona beam ionization (DCBI), the relatively novel ambient mass spectrometry (MS) technique, was utilized to screen for illicit additives in weight-loss food. The five usually abused chemicals, fenfluramine, N-di-desmethyl sibutramine, N-mono-desmethyl sibutramine, sibutramine, and phenolphthalein, were detected with the proposed DCBI-MS method. Fast single-sample and high-throughput analysis was demonstrated. Semi-quantification was accomplished based on peak areas in the ion

Hua Wang; Yongning Wu; Yong Zhao; Wenjian Sun; Li Ding; Bin Guo; Bo Chen

2012-01-01

40

Depletion of hepatic uridine diphosphoglucuronic acid decreases the biliary excretion of drugs.  

PubMed

Hepatic levels of uridine diphosphoglucuronic acid (UDPGA) in rats decreased substantially (greater than 80%) 40 min after galactosamine (GAL) (600 mg/kg i.p.) or after 1 hr of diethyl ether (DE) narcosis. Biliary excretion of several cholephils requiring glucuronidation before excretion was reduced by GAL 76, 62, 92, 90 and 97% for bilirubin, diethylstilbestrol, iopanoic acid, phenolphthalein and valproic acid, respectively. GAL treatment caused delayed plasma clearances of the parent compounds and reductions in plasma concentrations and biliary excretions of glucuronide conjugates. The degree of this reduction was related to the maximal excretion rate of the individual compounds. For phenolphthalein glucuronide and phenol-3,6-dibromphthalein disulfonate, which do not undergo conjugation, GAL had no effect on their biliary excretion. DE-induced UDPGA depletion had no effect on phenolphthalein glucuronide excretion but reduced that of phenol-3,6-dibromphthalein disulfonate 25%. DE did not affect the plasma elimination or biliary secretion of phenolphthalein. Of the other cholephils requiring conjugation, DE reduced the excretion of bilirubin, diethylstilbestrol, iopanoic acid and valproic acid by 41, 29, 76 and 28%, respectively. DE decreased the plasma elimination of the parent compounds and the appearance of the conjugates in both plasma and bile. Reduction of glucuronide excretion into bile was less pronounced at higher doses of the cholephilic anions. Neither treatment reduced in vitro hepatic UDP-glucuronosyltransferase activity toward these substrates or substantially altered extrahepatic UDPGA concentrations. Thus, both GAL and DE decreased UDPGA to similar concentrations, but the biliary excretion of compounds requiring glucuronidation before secretion was depressed to a greater extent by GAL. PMID:6405026

Gregus, Z; Watkins, J B; Thompson, T N; Klaassen, C D

1983-05-01

41

Invisible Ink Demonstration  

NSDL National Science Digital Library

In this chemistry demonstration, learners will discover that phenolphthalein is a chemical that displays different colors depending on the acidity or basicity of the environment. Learners will be surprised to see a "secret message" appear in bright pink ink when it is sprayed with Windex containing ammonia (a base). They compare this to what happens when the message is sprayed with Windex containing acetic acid (nothing!).

House, The S.

2013-05-15

42

Determination of mycophenolic acid glucuronide in microsomal incubations using high performance liquid chromatography–tandem mass spectrometry  

Microsoft Academic Search

A sensitive and specific HPLC–MS\\/MS method was developed for the analysis of mycophenolic acid glucuronide (MPAG) in incubations with human liver microsomes. Incubation samples were processed by protein precipitation with acetonitrile. MPAG and the internal standard phenolphthalein glucuronide were chromatographed on a C18 Synergi Fusion-RP column (100mm×2mm, 4?m) using gradient elution with a mixture of 1mM acetic acid in deionized

Mohamed-Eslam F. Mohamed; Stephen S. Harvey; Reginald F. Frye

2008-01-01

43

Sucrose, xylitol, and erythritol increase PMMA permeability for depot antibiotics.  

PubMed

Release of antibiotics from antibiotic-loaded PMMA is dependent on its permeability. Loading PMMA with soluble particulate filler has been proposed to increase permeability and antibiotic release for beads and spacers. We therefore assessed particulate sucrose, xylitol, and erythritol as fillers to increase the permeability and elution kinetics of filler-loaded PMMA. Based on lower solubility, we hypothesized that erythritol would not enhance permeability and elution as much as xylitol and sucrose. We made filler-loaded PMMA beads with each of the three fillers combined with phenolphthalein, and soaked in 0.1% NaOH solution. Permeability was assessed qualitatively by relative depth of phenolphthalein color change caused by penetration of NaOH solution into subsequently split beads. Elution was quantitatively assessed by spectrophotometric light absorption measurements of the eluent. Fluid penetration reached the center of 7-mm beads by day 15, similar for all three materials. Elution of phenolphthalein was greater for xylitol than for the other two materials. Particulate sucrose, xylitol, and erythritol fillers increase PMMA permeability and elution kinetics but relative solubility did not determine the relative degree of enhancement of permeability and elution by these materials. PMID:17549030

McLaren, Alex C; McLaren, Sandra G; Hickmon, Miranda K

2007-08-01

44

Nanocontainer-based corrosion sensing coating.  

PubMed

The present paper reports on the development of new sensing active coating on the basis of nanocontainers containing pH-indicating agent. The coating is able to detect active corrosion processes on different metallic substrates. The corrosion detection functionality based on the local colour change in active cathodic zones results from the interaction of hydroxide ions with phenolphthalein encapsulated in mesoporous nanocontainers which function as sensing nanoreactors. The mesoporous silica nanocontainers are synthesized and loaded with pH indicator phenolphthalein in a one-stage process. The resulting system is mesoporous, which together with bulkiness of the indicator molecules limits their leaching. At the same time, penetration of water molecules and ions inside the container is still possible, allowing encapsulated phenolphthalein to be sensitive to the pH in the surrounding environment and outperforming systems when an indicator is directly dispersed in the coating layer.The performed tests demonstrate the pH sensitivity of the developed nanocontainers being dispersed in aqueous solutions. The corrosion sensing functionality of the protective coatings with nanocontainers are proven for aluminium- and magnesium-based metallic substrates. As a result, the developed nanocontainers show high potential to be used in a new generation of active protective coatings with corrosion-sensing coatings. PMID:24045136

Maia, F; Tedim, J; Bastos, A C; Ferreira, M G S; Zheludkevich, M L

2013-09-17

45

Nanocontainer-based corrosion sensing coating  

NASA Astrophysics Data System (ADS)

The present paper reports on the development of new sensing active coating on the basis of nanocontainers containing pH-indicating agent. The coating is able to detect active corrosion processes on different metallic substrates. The corrosion detection functionality based on the local colour change in active cathodic zones results from the interaction of hydroxide ions with phenolphthalein encapsulated in mesoporous nanocontainers which function as sensing nanoreactors. The mesoporous silica nanocontainers are synthesized and loaded with pH indicator phenolphthalein in a one-stage process. The resulting system is mesoporous, which together with bulkiness of the indicator molecules limits their leaching. At the same time, penetration of water molecules and ions inside the container is still possible, allowing encapsulated phenolphthalein to be sensitive to the pH in the surrounding environment and outperforming systems when an indicator is directly dispersed in the coating layer. The performed tests demonstrate the pH sensitivity of the developed nanocontainers being dispersed in aqueous solutions. The corrosion sensing functionality of the protective coatings with nanocontainers are proven for aluminium- and magnesium-based metallic substrates. As a result, the developed nanocontainers show high potential to be used in a new generation of active protective coatings with corrosion-sensing coatings.

Maia, F.; Tedim, J.; Bastos, A. C.; Ferreira, M. G. S.; Zheludkevich, M. L.

2013-10-01

46

Visualization of turbulent reacting flow in a microscale nanoprecipitation reactor  

NASA Astrophysics Data System (ADS)

A flow visualization technique using the pH sensitive dye phenolphthalein was used to visualize and quantify turbulent reacting mixing in a microscale nanoprecipitation reactor. Phenolphthalein is colorless at pH lower than 8, but turns pink at higher pH, making it useful for visualizing acid-base reactions. Using this dye, turbulent reactive mixing in a confined impinging jets reactor (CIJR) was investigated. The reactor has two inlet streams, one at a pH of 3, and the other at a pH of 11. Phenolphthalein is also dissolved in both streams. A flash lamp with a extremely short pulse duration is used to freeze the turbulent motion of the fluids, and images are captured using a video camera. Quantitative mixing data are obtained by using a thresholding technique where local image intensities are transformed to binary signals which represent the local pH: 0 stands for pH lower than 8 and 1 for pH higher than 8. For each Reynolds number under consideration, thousands of realizations are acquired. Using this thresholding technique, probability density functions are obtained, allowing comparison to numerical simulations.

Shi, Yanxiang; Vishwanat, Somashekar; Olsen, Michael; Fox, Rodney

2009-11-01

47

Chemical test for mammalian feces in grain products: collaborative study.  

PubMed

A collaborative study was conducted to validate the use of the AOAC alkaline phosphatase method for mammalian feces in corn meal, 44.B01-44.B06, for 7 additional products: brown rice cream, oat bran, grits, semolina, pasta flour, farina, and barley plus (a mixture of barley, oat bran, and brown rice). The proposed method determines the presence of alkaline phosphatase, an enzyme contained in mammalian feces, by using phenolphthalein diphosphate as the enzyme substrate in a test agar medium. Fecal matter is separated from the grain products by specific gravity differences in 1% test agar. As the product is distributed on liquid test agar, fecal fragments float while the grain products sink. The alkaline phosphatase cleaves phosphate radicals from phenolphthalein diphosphate, generating free phenolphthalein, which produces a pink to red-purple color around the fecal particles in the previously colorless medium. Collaborators' recovery averages ranged from 21.7 particles (72.3%) for oat bran to 25.3 particles (84.3%) for semolina at the 30 particle spike level. Overall average background was 0.4 positive reactions per food type. The collaborators reported that the method was quick, simple, and easy to use. The method has been approved interim official first action for all 7 grain products. PMID:2808238

Gerber, H R

48

Chemical test for mammalian feces in ground black pepper: collaborative study.  

PubMed

A collaborative study for determining mammalian feces in ground black pepper was conducted, using a modified version of the AOAC Official Method 986.28 for mammalian feces in grain products. With the proposed method, the presence of alkaline phosphatase, an enzyme found in mammalian feces, was determined by using phenolphthalein diphosphate as the enzyme substrate in a test agar medium containing 1% agar in a borate buffer, pH 9.5. Ground black pepper was stirred in water to extract interfering color. The mixture was filtered and the residue was scattered on plates of liquid test agar. The alkaline phosphatase cleaved phosphate radicals from phenolphthalein diphosphate, generating free phenolphthalein, which appeared as pink to red-purple around the fecal particles in the previously colorless medium. For the 10- and 20-particle spike level, collaborators recovered averages of 12.3 and 24.1 particles, respectively. The experimental background was zero. Collaborators reported that the method was clear and easy to perform. PMID:7950416

Gerber, H R

49

New experimental evidence about secondary processes in phenylphthalein-dimethylether and 1,1'-bis(p-methoxyphenyl)cyclohexane.  

PubMed

The slow secondary (beta) process of 1,1'-bis (4-methoxyphenyl) cyclohexane and phenolphthalein dimethylether has been investigated by dielectric spectroscopy. New experimental results about the pressure dependence of the two processes are reported, as well as new data about the dependence of the characteristic relaxation frequency on the cooling rate used to vitrify the system in isobaric conditions. Previous investigations on these systems suggested that the first one is not a true Johari-Goldstein relaxation and both processes should originate from the flip flop motion of the phenyl ring. The results herein reported evidence that the characteristic frequency of the beta process of phenolphthalein dimethylether is more sensitive to pressure variation and to the vitrification procedure than that of 1,1'-bis (4-methoxyphenyl) cyclohexane. Such results suggest an intermolecular origin for the secondary process in phenolphthalein dimethylether and an intramolecular origin for the other one, which do not completely agree with the previous interpretation. We evidence that the microscopic mechanism at the basis of these two processes is still an open question, which should be debated on the basis of new experimental investigations. PMID:17887857

Prevosto, D; Sharifi, S; Capaccioli, S; Rolla, P A; Hensel-Bielowka, S; Paluch, M

2007-09-21

50

New experimental evidence about secondary processes in phenylphthalein-dimethylether and 1,1'-bis(p-methoxyphenyl)cyclohexane  

NASA Astrophysics Data System (ADS)

The slow secondary (?) process of 1,1'-bis (4-methoxyphenyl) cyclohexane and phenolphthalein dimethylether has been investigated by dielectric spectroscopy. New experimental results about the pressure dependence of the two processes are reported, as well as new data about the dependence of the characteristic relaxation frequency on the cooling rate used to vitrify the system in isobaric conditions. Previous investigations on these systems suggested that the first one is not a true Johari-Goldstein relaxation and both processes should originate from the flip flop motion of the phenyl ring. The results herein reported evidence that the characteristic frequency of the ? process of phenolphthalein dimethylether is more sensitive to pressure variation and to the vitrification procedure than that of 1,1'-bis (4-methoxyphenyl) cyclohexane. Such results suggest an intermolecular origin for the secondary process in phenolphthalein dimethylether and an intramolecular origin for the other one, which do not completely agree with the previous interpretation. We evidence that the microscopic mechanism at the basis of these two processes is still an open question, which should be debated on the basis of new experimental investigations.

Prevosto, D.; Sharifi, S.; Capaccioli, S.; Rolla, P. A.; Hensel-Bielowka, S.; Paluch, M.

2007-09-01

51

Limitations in the use of color indicators in gastric analysis  

Microsoft Academic Search

Conclusions and Summary  \\u000a \\u000a \\u000a \\u000a 1. \\u000a \\u000a The end points of the color indicators dimethyl-aminoazobenzene (Töper’s reagent) and phenol-phthalein are uncertain. Even\\u000a a single observer making repeated observations of a selected color end point from color memory alone is liable to a range\\u000a of error of approximately a full pH unit. With dimethyl-aminoazobenzene this range of error expressed in equivalent clinical\\u000a values may

J. Edward Berk; J. Earl Thomas; MARTIN E. REttFUSS

1942-01-01

52

Ammonia (GCMP)  

NSDL National Science Digital Library

Ammonia fountain: this is a resource in the collection "General Chemistry Multimedia Problems". In an ammonia fountain, a flask is filled with ammonia gas. A tube from the flask extends into a pan of water that contains phenolphthalein. When a rubber bulb full of water is squeezed, the water squirts into the flask. Water from the pan then is pushed into the flask and the indicator changes color. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

53

Tracking a Virus  

NSDL National Science Digital Library

Students simulate the spread of a virus such as HIV through a population by âsharingâ (but not drinking) the water in a plastic cup with several classmates. Although invisible, the water in a few of the cups will already be tainted with the âvirusâ (sodium carbonate). After all the students have shared their liquids, the contents of the cups will be tested for the virus with phenolphthalein, a chemical that causes a striking color change in the presence of sodium carbonate. Students will then set about trying to determine which of their classmates were the ones originally infected with the virus.

Engineering K-Ph.d. Program

54

Boundary layer visualization and mass transfer studies on a rotating electroplating mandrel: Exploratory experimentation and technique development  

SciTech Connect

An electrochemical technique for visualization of the laminar diffusion (concentration) boundary layer on a rotating mandrel is described. This technique utilizes the change in pH near the surface associated with formation of an alkaline solution formed by electrolysis of dilute sodium chloride solution at the rotating cathode. The alkaline boundary layer is made visible by phenolphthalein indicator. Development of a technique suitable for determining mass transfer rates on a rotating mandrel of arbitrary axisymmetric contour is also described. This technique utilizes dissolution of a thin coating of benzoic acid in water and has applicability to modeling of an electroplating process.

Keyes, J.L. Jr.; Capps, G.J.; Johnson, B.L. Sr.; White, C.P.

1987-04-01

55

Determination of Chlorinity of Water without the Use of Chromate Indicator  

PubMed Central

A new method for determining chlorinity of water was developed in order to improve the old method by alleviating the environmental problems associated with the toxic chromate. The method utilizes a mediator, a weak acid that can form an insoluble salt with the titrant. The mediator triggers a sudden change in pH at an equivalence point in a titration. Thus, the equivalence point can be determined either potentiometrically (using a pH meter) or simply with an acid-base indicator. Three nontoxic mediators (phosphate, EDTA, and sulfite) were tested, and optimal conditions for the sharpest pH changes were sought. A combination of phosphate (a mediator) and phenolphthalein (an indicator) was found to be the most successful. The choices of the initial pH and the concentration of the mediator are critical in this approach. The optimum concentration of the mediator is ca. 1~2?mM, and the optimum value of the initial pH is ca. 9 for phosphate/phenolphthalein system. The method was applied to a sample of sea water, and the results are compared with those from the conventional Mohr-Knudsen method. The new method yielded chlorinity of a sample of sea water of (17.58 ± 0.22)?g/kg, which is about 2.5% higher than the value (17.12 ± 0.22) g/kg from the old method.

Hong, Tae-Kee; Kim, Myung-Hoon; Czae, Myung-Zoon

2010-01-01

56

Structure-Based Discovery of Inhibitors of Thymidylate Synthase  

NASA Astrophysics Data System (ADS)

A molecular docking computer program (DOCK) was used to screen the Fine Chemical Directory, a database of commercially available compounds, for molecules that are complementary to thymidylate synthase (TS), a chemotherapeutic target. Besides retrieving the substrate and several known inhibitors, DOCK proposed putative inhibitors previously unknown to bind to the enzyme. Three of these compounds inhibited Lactobacillus caser TS at submillimolar concentrations. One of these inhibitors, sulisobenzone, crystallized with TS in two configurations that differed from the DOCK-favored geometry: a counterion was bound in the substrate site, which resulted in a 6 to 9 angstrom displacement of the inhibitor. The structure of the complexes suggested another binding region in the active site that could be exploited. This region was probed with molecules sterically similar to sulisobenzone, which led to the identification of a family of phenolphthalein analogs that inhibit TS in the 1 to 30 micromolar range. These inhibitors do not resemble the substrates of the enzyme. A crystal structure of phenolphthalein with TS shows that it binds in the target site in a configuration that resembles the one suggested by DOCK.

Shoichet, Brian K.; Stroud, Robert M.; Santi, Daniel V.; Kuntz, Irwin D.; Perry, Kathy M.

1993-03-01

57

Active oxygen doctors the evidence  

NASA Astrophysics Data System (ADS)

Investigation at the scene of a crime begins with the search for clues. In the case of bloodstains, the most frequently used reagents are luminol and reduced phenolphthalein (or phenolphthalin that is also known as the Kastle-Meyer colour test). The limitations of these reagents have been studied and are well known. Household cleaning products have evolved with the times, and new products with active oxygen are currently widely used, as they are considered to be highly efficient at removing all kinds of stains on a wide range of surfaces. In this study, we investigated the possible effects of these new cleaning products on latent bloodstains that may be left at a scene of a crime. To do so, various fabrics were stained with blood and then washed using cleaning agents containing active oxygen. The results of reduced phenolphthalein, luminol and human haemoglobin tests on the washed fabrics were negative. The conclusion is that these new products alter blood to such an extent that it can no longer be detected by currently accepted methods employed in criminal investigations. This inability to locate bloodstains means that highly important evidence (e.g. a DNA profile) may be lost. Consequently, it is important that investigators are aware of this problem so as to compensate for it.

Castelló, Ana; Francès, Francesc; Corella, Dolores; Verdú, Fernando

2009-02-01

58

Thermal mixing in a stratified environment  

NASA Astrophysics Data System (ADS)

Laboratory experiments of a thermal impinging on a stratified interface have been performed. The thermal was released from a cylindrical reservoir located at the bottom of a Lucite tank. The stratified interface was created by filling the tank with two different saline solutions. The density of the lower layer is greater than that of the upper layer and the thermal fluid, thereby creating a stable stratification. A pH indicator, phenolphthalein, is used to visualize and quantify the amount of mixing produced by the impingement of the thermal at the interface. The upper layer contains a mixture of water, salt and sodium hydroxide. The thermal fluid is composed of water, sulfuric acid and phenolphthalein. When the thermal entrains and mixes fluid from the upper layer, a chemical reaction takes place, and the resulting mixed fluid is now visible. The ratio of base to acid, called the equivalence ratio, was varied throughout the experiments, as well as the Richardson number. The Richardson number is the ratio of potential to kinetic energy, and is based on the thermal quantities at the interface. Results indicate that the amount of mixing produced is proportional to the Richardson number raised to the -3/2 power. Previous experiments (Zhang and Cotel 1999) revealed that the entrainment rate of a thermal in a stratified environment follows the same power law.

Kraemer, Damian; Cotel, Aline

1999-11-01

59

Determination of Chlorinity of Water without the Use of Chromate Indicator.  

PubMed

A new method for determining chlorinity of water was developed in order to improve the old method by alleviating the environmental problems associated with the toxic chromate. The method utilizes a mediator, a weak acid that can form an insoluble salt with the titrant. The mediator triggers a sudden change in pH at an equivalence point in a titration. Thus, the equivalence point can be determined either potentiometrically (using a pH meter) or simply with an acid-base indicator. Three nontoxic mediators (phosphate, EDTA, and sulfite) were tested, and optimal conditions for the sharpest pH changes were sought. A combination of phosphate (a mediator) and phenolphthalein (an indicator) was found to be the most successful. The choices of the initial pH and the concentration of the mediator are critical in this approach. The optimum concentration of the mediator is ca. 1~2?mM, and the optimum value of the initial pH is ca. 9 for phosphate/phenolphthalein system. The method was applied to a sample of sea water, and the results are compared with those from the conventional Mohr-Knudsen method. The new method yielded chlorinity of a sample of sea water of (17.58 ± 0.22)?g/kg, which is about 2.5% higher than the value (17.12 ± 0.22) g/kg from the old method. PMID:21461358

Hong, Tae-Kee; Kim, Myung-Hoon; Czae, Myung-Zoon

2011-03-02

60

Qualitative screening for adulterants in weight-loss supplements by ion mobility spectrometry.  

PubMed

Ion mobility spectrometry (IMS) served as a rapid, qualitative screening tool for the analysis of adulterated weight-loss products. We have previously shown that sibutramine extracted into methanol from dietary supplements can be detected at low levels (2ng) using a portable IMS spectrometer, and have adapted a similar method for the analysis of additional weight-loss product adulterants. An FDA collaborative study helped to define the limits for fluoxetine with a limit of detection of 2ng. We also evaluated more readily available, less toxic extraction solvents and found isopropanol and water were comparable to methanol. Isopropanol was favored over water for two reasons: (1) water increases the analysis time and (2) aqueous solutions were more susceptible to pH change, which affected the detection of sibutramine. In addition to sibutamine and fluoxetine, we surveyed 11 weight-loss adulterants; bumetanide, fenfluramine, furosemide, orlistat, phenolphthalein, phentermine, phenytoin, rimonabant, sertraline and two sibutramine analogs, desmethylsibutramine and didesmethylsibutramine, using portable and benchtop ion mobility spectrometers. Out of these 13 active pharmaceutical ingredients (APIs), portable and benchtop ion mobility spectrometers were capable of screening products for 10 of these APIs. The developed procedure was applied to two weight-loss dietary supplements using both portable and benchtop instruments. One product contained didesmethylsibutramine while the other contained didesmethylsibutramine and phenolphthalein. PMID:22902504

Dunn, Jamie D; Gryniewicz-Ruzicka, Connie M; Mans, Daniel J; Mecker-Pogue, Laura C; Kauffman, John F; Westenberger, Benjamin J; Buhse, Lucinda F

2012-08-06

61

Xenbiotic metabolism in microsomes and isolated nuclei after hepatic insult  

SciTech Connect

A technique is described for the isolation of rat hepatic nuclei providing a very pure organelle preparation containing extremely low levels of other organelle contamination. Five methods for determining the purity of the nuclear preparation are described. The metabolism of /sup 14/C-N,N'-dimethylphenobarbital (DMPB) by a nuclear NADPH-dependent cytochrome P450-mediated N-demethylation reaction was investigated. The radiometric assay to measure metabolism was rapid and convenient. The primary metabolite is methylphenobarbital. No other metabolites were detected by HPLC at the specific activity employed (4.0 uCi/mg). /sup 14/C-DMPB was shown to be a superior substrate over ethylmorphine for the determination of nuclear N-demethylation. Glucuronide conjugation of phenolphthalein (PHE) in nuclear and microsomal preparations was described. Phenolphthalein was metabolized by nuclei and microsomes, to only one product, the glucuronide, under the conditions employed. /sup 3/H-Benzo(a)pyrene (B(a)P) was shown to be metabolized by nuclear and microsomal preparations by an NADPH-dependent mechanism to reactive species. The effects of three chemical hepatic insults on microsomal and nuclear metabolism of DMPB, PHE, and B(a)P are described. Theories are proposed which describe the mechanisms involved in the production of the effects observed for the three hepatic insults.

Arnold, M.E.

1985-01-01

62

Development and the Educational Effect of a System of the Corrosion of Iron and the Anti-corrosion Ability of Conductive Polymer Polyaniline  

NASA Astrophysics Data System (ADS)

Few general chemistry textbooks of high schools, colleges and universities introduce the corrosion of iron into the oxidation-reduction (redox) section, although the corrosion is very popular phenomena for students. Besides, no description appears about conductive polymers as anti-corrosion materials. The corrosion is a redox reaction proceeding through the local cell mechanism : the iron oxidation half-cell reaction at the local anode and the reduction of oxygen at the local cathode. To prepare a teaching tool for understanding of the mechanism, the visualization of the corrosion was attempted using phenolphthalein and potassium hexacyanoferrate (III) as color couplers for the anodic and cathodic products : Fe2+ and OH-. The local anode and cathode were obviously shown as gradual blue and red coloration when commercial nails were soaked in 4% NaCl aqueous solution containing phenolphthalein and potassium hexacyanoferrate (III) . On the other hand, no coloration occurred for the nail covered with a conductive polymer polyaniline. To know the anti-corrosion mechanism, the open-circuit potential of the nail was measured. The fact that the potential was kept at the potential range where iron was passivated implied that polyaniline acted as an in-situ oxidant. The visualization was experimentally performed at an actual chemistry class and the utility value was estimated. As a result, the visualization is expected to be a useful teaching tool for the corrosion and the understanding of the role of polyaniline as the anti-corrosion material.

Yano, Jun; Nakamura, Noriyuki; Yamazaki, Suzuko; Ichimori, Hayato; Osaki, Nobukazu; Okano, Hiroshi

63

Effect of Dielectric Constant and Ionic Strength Variation on the Fading of N,N-Dimethylaminophenolphthalein in Alkaline Medium  

NASA Astrophysics Data System (ADS)

Based on the Bronsted-Christiansen-Scatchard equation the influence of the ionic strength I and the permittivity e (dielectric constant) on the rate of ionic reactions has been studied. Experiments carried out by students have shown that the application of N,N-dimethylaminophenolphtalein (DMAPP) instead of the usually used phenolphthalein provides more pertinent results visualizing the role of the salt effect by the consideration of the rate of ionic reaction. A modified route for the preparation of DMAPP as well as the procedure for the performance of the fading experiment have been described. Furthermore, the results obtained from Student's experiments demonstrating the influence of I and e of the solvent on the rate constant k have been presented and discussed.

Dakkouri, M.; Bodenmuller, W.

1997-05-01

64

A plate method for screening of bacteria capable of degrading aliphatic nitriles.  

PubMed

A novel indicator plate method was developed for screening of aliphatic-nitrile-degrading bacteria. Isolated bacteria were tested for utilization of acetonitrile as sole source of carbon and nitrogen with the release of ammonia. The released ammonia causes increase of the pH of the medium. Phenol red indicator is used for detection of ammonia based on colour change of the indicator dye from red to pink. The liberation of ammonia from aliphatic-nitrile-utilizing bacteria is also studied in plates containing other indicators such as bromothymol blue and phenolphthalein. The usefulness of the indicator plate is demonstrated for bacteria that degrade certain aliphatic nitriles. Bacteria degrading nitriles as a nitrogen source can also be isolated with a medium containing additional carbon source. This plate method would be useful in isolation and screening of bacteria for degradation of aliphatic nitriles and also for production of nitrile-hydrolyzing enzymes. PMID:19921293

Santoshkumar, M; Nayak, Anand S; Anjaneya, O; Karegoudar, Timmanagouda B

2009-11-17

65

Detection of bacterial phosphatase activity by means of an original and simple test.  

PubMed Central

A new test for the detection of bacterial phosphatase activity has been devised. The test is performed using agar media containing both methyl green (MG) and phenolphthalein diphosphate (PDP); in these media phosphatase-producing strains grow deep-green-stained colonies whereas non-producing strains do not. A total of 739 different strains were tested, including 593 staphylococci, 95 micrococci, 11 streptococci, 10 corynebacteria, 14 enterobacteria, and 16 candidae. All strains found phosphatase-positive according to the conventional phosphatase test displayed deep-green-stained colonies on MG-PDP media, whereas all phosphatase-negative strains showed unstained colonies on the same media. The main advantages of the present phosphatase test as compared with other conventional ones are that it is more simple to perform, it can reveal the phosphatase activity of colonies grown in deep agar, and can be incorporated into commercial multitest kits.

Satta, G; Grazi, G; Varaldo, P E; Fontana, R

1979-01-01

66

Sequestration of CO2 by concrete carbonation.  

PubMed

Carbonation of reinforced concrete is one of the causes of corrosion, but it is also a way to sequester CO2. The characteristics of the concrete cover should ensure alkaline protection for the steel bars but should also be able to combine CO2 to a certain depth. This work attempts to advance the knowledge of the carbon footprint of cement. As it is one of the most commonly used materials worldwide, it is very important to assess its impact on the environment. In order to quantify the capacity of cement based materials to combine CO2 by means of the reaction with hydrated phases to produce calcium carbonate, Thermogravimetry and the phenolphthalein indicator have been used to characterize several cement pastes and concretes exposed to different environments. The combined effect of the main variables involved in this process is discussed. The moisture content of the concrete seems to be the most influential parameter. PMID:20225850

Galan, Isabel; Andrade, Carmen; Mora, Pedro; Sanjuan, Miguel A

2010-04-15

67

Prediction of corrosion rates of water distribution pipelines according to aggressive corrosive water in Korea.  

PubMed

The drinking water network serving Korea has been used for almost 100 years. Therefore, pipelines have suffered various degrees of deterioration due to aggressive environments. The pipe breaks were caused by in-external corrosion, water hammer, surface loading, etc. In this paper, we focused on describing corrosion status in water distribution pipes in Korea and reviewing some methods to predict corrosion rates. Results indicate that corrosive water of lakes was more aggressive than river water and the winter was more aggressive compared to other seasons. The roughness growth rates of Dongbok lake showed 0.23 mm/year. The high variation of corrosion rates is controlled by the aging pipes and smaller diameter. Also the phenolphthalein test on a cementitious core of cement mortar lined ductile cast iron pipe indicated the pipes over 15 years old had lost 50-100% of their lime active cross sectional area. PMID:14982159

Chung, W S; Yu, M J; Lee, H D

2004-01-01

68

Alteration of expirated bloodstain patterns by Calliphora vicina and Lucilia sericata (Diptera: Calliphoridae) through ingestion and deposition of artifacts.  

PubMed

Bloodstain pattern analysis can provide insight into a sequence of events associated with a violent crime. However, bloodstain pattern analysis can be confounded by the feeding activity of blow flies. We conducted two laboratory experiments to investigate the relationships between Lucilia sericata (green bottle fly) and Calliphora vicina (blue bottle fly), expirated bloodstains, and pooled bloodstains on a range of surfaces (linoleum, wallpaper, textured paint). C. vicina and L. sericata changed bloodstain pattern morphology through feeding and defecation. They also deposited artifacts in rooms where blood was not present originally. Chemical presumptive tests (Hemastix(®) , phenolphthalein, leucocrystal violet, fluorescein) were not able to differentiate between insect artifacts and bloodstains. Thus, C. vicina and L. sericata can confound bloodstain pattern analysis, crime scene investigation, and reconstruction. Crime scene investigators should be aware of these fundamental behaviors, and the effects that blow flies can have on expirated and pooled bloodstain patterns. PMID:21039518

Striman, Becca; Fujikawa, Amanda; Barksdale, Larry; Carter, David O

2010-10-06

69

Synthesis, characterization, and controllable drug release of pH-sensitive hybrid magnetic nanoparticles  

NASA Astrophysics Data System (ADS)

The synthesis of magnetite nanoparticles coated with pH-sensitive poly((2-dimethylamino) ethyl methacrylate) (PDMAEMA) via atom transfer radical polymerization (ATRP) for use as novel potential carriers for targeted drug delivery and controllable release is reported. The organic/inorganic hybrid nanoparticles were obtained with a narrow molecular weight distribution. The pH-sensitivity of the nanoparticles was investigated by the measurement of the pH dependence of hydrodynamic radius and the superparamagnetism was illustrated by vibrating sample magnetometer (VSM). The behavior of model drug phenolphthalein released from the nanoparticles indicated that the rate of drug release could be effectively controlled by altering the pH values of the environment.

Zhou, Lilin; Yuan, Jinying; Yuan, Weizhong; Sui, Xiaofeng; Wu, Sizhu; Li, Zhaolong; Shen, Dezhong

2009-09-01

70

An improved microfluidics approach for monitoring real-time interaction profiles of ultrafast molecular recognition.  

PubMed

Our study illustrates the development of a microfluidics (MF) platform combining fluorescence microscopy and femtosecond/picosecond-resolved spectroscopy to investigate ultrafast chemical processes in liquid-phase diffusion-controlled reactions. By controlling the flow rates of two reactants in a specially designed MF chip, sub-100 ns time resolution for the exploration of chemical intermediates of the reaction in the MF channel has been achieved. Our system clearly rules out the possibility of formation of any intermediate reaction product in a so-called fast ionic reaction between sodium hydroxide and phenolphthalein, and reveals a microsecond time scale associated with the formation of the reaction product. We have also used the developed system for the investigation of intermediate states in the molecular recognition of various macromolecular self-assemblies (micelles) and genomic DNA by small organic ligands (Hoechst 33258 and ethidium bromide). We propose our MF-based system to be an alternative to the existing millisecond-resolved "stopped-flow" technique for a broad range of time-resolved (sub-100 ns to minutes) experiments on complex chemical?biological systems. PMID:22559521

Batabyal, Subrata; Rakshit, Surajit; Kar, Shantimoy; Pal, Samir Kumar

2012-04-01

71

Prevalence of surreptitious laxative abuse in patients with diarrhoea of uncertain origin: a cost benefit analysis of a screening procedure.  

PubMed Central

The costs and medical benefits of an early, routine laxative screening test in patients with diarrhoea of uncertain origin was evaluated. During a two year period 200 consecutive, unselected patients complaining of diarrhoea were considered for the study in whom a three day faecal collection was undertaken. Fifty four patients denying laxative consumption had diarrhoea (mean daily stool weight greater than 200 g) of uncertain origin at their initial visit of whom 47 were screened to detect ingestion of anthraquinones, bisacodyl, phenolphthalein, and magnesium salts. Seven patients had positive tests. No single clinical feature could have predicted the outcome of the test. The possible cost savings of the programme were estimated by not releasing the results of the test to the clinicians until the patient's investigations were complete. The seven patients with laxative abuse spent a total of 35 days in hospital and were seen on 29 occasions in the outpatient clinic after the laxative screening test was positive. The cost of the screening programme was cheaper than the costs of the diagnostic procedures in patients with laxative abuse. We recommend the use of a comprehensive, early laxative screening programme in all patients with diarrhoea of uncertain origin as a cost effective procedure.

Bytzer, P; Stokholm, M; Andersen, I; Klitgaard, N A; Schaffalitzky de Muckadell, O B

1989-01-01

72

The prevalence of visible and/or occult blood on anesthesia and monitoring equipment.  

PubMed

The Occupational Safety and Health Administration (OSHA) and the Centers for Disease Control and Prevention (CDC) have attempted to stop the spread of blood-borne pathogens by issuing several recommendations and regulations. However, unless healthcare workers comply with these standards, they are not effective. In the anesthesia care environment, the anesthetist is responsible for ensuring that the equipment is clean, and disinfected, before use. We studied the prevalence of visible and occult blood on 6 types of anesthesia and monitoring equipment identified as ready for use in 28 operating suites, in 2 facilities. The sample consisted of 336 observations of the 6 types of equipment. The equipment was inspected for visible blood and then tested for occult blood using a 3-stage phenolphthalein test. Of the 336 observations, 110 (32.7%), were positive for occult blood with only 6 showing visible blood. The presence of blood on this equipment may be in direct violation of the OSHA Blood-borne Pathogen Standard and the infection control guidelines of the American Association of Nurse Anesthetists. Furthermore, the presence of blood on this equipment may increase the risk for nosocomial and occupational exposure to viral and bacterial pathogens. Recommendations were made to decrease the risks from this contamination by redesigning equipment, increasing the use of disposable equipment, and ensuring compliance with effective infection control practices. PMID:11759138

Perry, S M; Monaghan, W P

2001-02-01

73

A split and recombination micromixer fabricated in a PDMS three-dimensional structure  

NASA Astrophysics Data System (ADS)

In this paper we propose a new split and recombination (SAR) micromixer that is compatible with the microfabrication process of polydimethylsiloxane (PDMS). We evaluate the mixing efficiency of the fabricated SAR micromixer and find that it increases interfaces exponentially. Simulation using CFD-ACE+ shows a cross-sectional view of the flow and estimates the mixing efficiency of the SAR micromixer and the pressure drop for a unit of the SAR micromixer. A mixing experiment involving phenolphthalein and NaOH solutions shows that interfaces, represented as red lines, are increased by SAR mixing. The result of our mixing experiment involving blue dye and water is evaluated to determine the mixing efficiency by calculating the standard deviation (stdev) of the pixel intensity of the observed image. After the seventh unit of the SAR micromixer, solutions are mixed to 90% at Re 0.6. The number of units needed to reach a mixed state in which the stdev is lower than 0.05, a 90% mixed state, increases from 5 to 10 for a flow rate ranging from 0.1 µell min-1 (Re 0.012) to 1000 µell min-1 (Re 120) including numerical analysis results. The pressure drop increases proportionally from 2.8 Pa to 35 000 Pa when the flow rate increases from 0.1 µell min-1 (Re 0.012) to 1000 µell min-1 (Re 120) in the numerical analysis results.

Lee, Seok Woo; Kim, Dong Sung; Lee, Seung S.; Kwon, Tai Hun

2006-05-01

74

Electric charge-mediated coalescence of water droplets for biochemical microreactors  

PubMed Central

This work proposes the use of charged droplets driven by the Coulombic force as solution-phase reaction chambers for biological microreactions. A droplet can be charged near an electrode under dc voltage by direct contact to the electrode. This process is called electrical charging of droplet (ECOD). This charged droplet can then be transported rapidly between electrodes following the arc of an electric field line by exploiting electrostatic force. As on-demand electrocoalescence, both alkalization of phenolphthalein and bioluminescence reaction of luciferase in the presence of adenosine triphosphate are studied to test the feasibility of the biochemical microreactors using ECOD. Two oppositely charged droplets are merged to have a color change immediately after microchemical reaction. The applicability of an ECOD-driven droplet to measurement of glucose concentration is also tested. The glucose concentration is measured using a colorimetric enzyme-kinetic method based on Trinder’s reaction [J. Clin. Pathol. 22, 158 (1969)]. The color change in the merged droplet is detected with an absorbance measurement system consisting of a photodiode and a light emitting diode.

Jung, Yong-Mi; Kang, In Seok

2010-01-01

75

Time evolution of the fractal dimension of a mixing front  

NASA Astrophysics Data System (ADS)

We present a description of an experimental study of an array of turbulent plumes (from one to nine plumes), investigating the time evolution of the fractal dimension of the plumes and also the spatial evolution of the fractal dimension from one plume to other. We also investigate the effects of bouyancy (different Atwood numbers), the number of plumes and the height of the bouyancy source on the fractal dimension. The plumes are formed by injecting a dense fluid from a small source (from one to nine orifices) into a stationary body of lighter brime (saline solution) contained in a tank. The source fluid was dyed with fluorescein and we use the LIF technique. The plumes were fully turbulent and we have both momentum and bouyancy regimes. The fractal dimensions of contours of concentration were measured. The fractal analysis of the turbulent convective plumes was performed with the box counting algorithm for different intensities of evolving plume images using the special software Ima_Calc. Fractal dimensions between 1.3 and 1.35 are obtained from box counting methods for free convection and neutral boundary layers. Other results have been published which use the box counting method to analyze images of jet sections -produced from LIF techniques. The regions where most of the mixing takes place are also compared with Reactive flow experiments using phenolphthalein and acid-base interfaces performed by Redondo(1994) IMA 43. Eds M. Farge, JC Hunt and C. Vassilicos.

Lopez Gonzalez-Nieto, P.; Grau, J.

2009-04-01

76

Analysis of adulterated herbal medicines and dietary supplements marketed for weight loss by DOSY 1H-NMR.  

PubMed

Twenty herbal medicines or dietary supplements marketed as natural slimming products were analysed by diffusion ordered spectroscopy (DOSY) 1H-nuclear magnetic resonance (NMR) and DOSY-COSY 1H-NMR. The method allows analysis of the whole sample with the detection of both active and inactive ingredients in these complex matrices. Among the 20 formulations analysed, two were strictly herbal and four had a composition corresponding to declared ingredients on the packaging or the leaflet. The others were all adulterated. Eight formulations contain sibutramine alone at doses ranging from 4.4 to 30.5 mg/capsule. Five formulations contain sibutramine (from 5.0 to 19.6 mg/capsule or tablet) in combination with phenolphthalein (from 4.4 to 66.1 mg/capsule), and the last formulation was adulterated with synephrine (19.5 mg/capsule). Quantification of the actives was carried out with 1H-NMR. Several other compounds were also characterized including methylsynephrine, vitaberin, sugars, vitamins, etc. DOSY NMR is thus proposed as a useful tool for detection of unexpected adulteration. PMID:20437283

Vaysse, J; Balayssac, S; Gilard, V; Desoubdzanne, D; Malet-Martino, M; Martino, R

2010-07-01

77

Improved characterization technique for micromixers  

NASA Astrophysics Data System (ADS)

This paper reports an improved technique to characterize a micromixer. Due to the small dimensions of micromixers, the mixing relies on diffusion only. To date most diffusive micromixers have been tested with phenolphthalein and a base. However, this method does not give any information about the proportional mixing of the device, as the final colour of the mixing depends only on the pH value. For a pH below the critical point, the mixed fluid is colourless, whereas an intensive but almost constant colour is obtained at pH values above. In order to avoid any chemical reactions, the new characterization technique is based on commercially available inks of different colours. For mixing, the colours of the inks change gradually rather than at one specific point. The technique has been successfully employed to characterize a micromixer at various pressure differences. Finally, image processing was used to allow observation of proportional mixing and to characterize the development of the diffusion over time. The latter feature could be an interesting technique to monitor the course of a reaction over the length of the mixer (stopped flow technique).

Koch, M.; Witt, H.; Evans, A. G. R.; Brunnschweiler, A.

1999-06-01

78

Large-surface mesoporous TiO2 nanoparticles: synthesis, growth and photocatalytic performance.  

PubMed

This study demonstrates a facile and effective method to generate mono-dispersed titanium dioxide spheres at ambient conditions. The size of the colloids can be controlled from 60 to 500 nm by optimizing experimental parameters (e.g., concentration, time, and temperature). Anatase TiO(2) can be obtained through titanium glycolate colloids generated in acetone via two ways: water boiling approach and calcination at a high temperature of 500°C. Particle characteristics (shape, size, and size distribution) were measured by advanced techniques, including transmission electron microscope (TEM), thermo-gravimetric analysis (TGA), UV/Vis absorption spectrum, nitrogen gas adsorption and desorption isotherms Brunauer-Emmett-Teller (BET) surface area measurement, and X-ray diffraction technique (XRD). The possible mechanism of nucleation and growth of such colloids was discussed. The role of acetone in the formation and growth of titanium glycolate colloids was also investigated by Fourier transform infrared (FT-IR) spectroscopy. Finally, the photocatalysis performance of such anatase TiO(2) particles was tested and proved to be efficient in degradation of organic dyes (e.g., phenolphthalein and methly orange). PMID:22975400

Yang, Xiaohong; Fu, Haitao; Yu, Aibing; Jiang, Xuchuan

2012-07-25

79

Polymeric redox-responsive delivery systems bearing ammonium salts cross-linked via disulfides.  

PubMed

A redox-responsive polycationic system was synthesized via copolymerization of N,N-diethylacrylamide (DEAAm) and 2-(dimethylamino)ethyl methacrylate (DMAEMA). N,N'-bis(4-chlorobutanoyl)cystamine was used as disulfide-containing cross-linker to form networks by the quaternization of tertiary amine groups. The insoluble cationic hydrogels become soluble by reduction of disulfide to mercaptanes by use of dithiothreitol (DTT), tris(2-carboxyethyl)phosphine (TCEP) or cysteamine, respectively. The soluble polymeric system can be cross-linked again by using oxygen or hydrogen peroxide under basic conditions. The redox-responsive polymer networks can be used for molecular inclusion and controlled release. As an example, phenolphthalein, methylene blue and reactive orange 16 were included into the network. After treatment with DTT a release of the dye could be recognized. Physical properties of the cross-linked materials, e.g., glass transition temperature (T g), swelling behavior and cloud points (T c) were investigated. Redox-responsive behavior was further analyzed by rheological measurements. PMID:24062825

Dollendorf, Christian; Hetzer, Martin; Ritter, Helmut

2013-08-13

80

A serpentine laminating micromixer combining splitting/recombination and advection.  

PubMed

Mixing enhancement has drawn great attention from designers of micromixers, since the flow in a microchannel is usually characterized by a low Reynolds number (Re) which makes the mixing quite a difficult task to accomplish. In this paper, a novel integrated efficient micromixer named serpentine laminating micromixer (SLM) has been designed, simulated, fabricated and fully characterized. In the SLM, a high level of efficient mixing can be achieved by combining two general chaotic mixing mechanisms: splitting/recombination and chaotic advection. The splitting and recombination (in other terms, lamination) mechanism is obtained by the successive arrangement of "F"-shape mixing units in two layers. The advection is induced by the overall three-dimensional serpentine path of the microchannel. The SLM was realized by SU-8 photolithography, nickel electroplating, injection molding and thermal bonding. Mixing performance of the SLM was fully characterized numerically and experimentally. The numerical mixing simulations show that the advection acts favorably to realize the ideal vertical lamination of fluid flow. The mixing experiments based on an average mixing color intensity change of phenolphthalein show a high level of mixing performance was obtained with the SLM. Numerical and experimental results confirm that efficient mixing is successfully achieved from the SLM over the wide range of Re. Due to the simple and mass producible geometry of the efficient micromixer, SLM proposed in this study, the SLM can be easily applied to integrated microfluidic systems, such as micro-total-analysis-systems or lab-on-a-chip systems. PMID:15970967

Kim, Dong Sung; Lee, Se Hwan; Kwon, Tai Hun; Ahn, Chong H

2005-04-26

81

A chaotic micromixer using obstruction-pairs  

NASA Astrophysics Data System (ADS)

A micromixer is one of the most important components for a chemical and/or diagnostic analysis in microfluidic devices such as a micro-total-analysis-system and a lab-on-a-chip. In this paper, a novel chaotic micromixer is developed in a simple design by introducing obstruction-pairs on the bottom of a microchannel. An obstruction-pair, which is composed of two hexahedron blocks arranged in an asymmetric manner, can induce a rotational flow along the down-channel direction due to the anisotropy of flow resistance. By utilizing this characteristic of the obstruction-pair, four mixing units are designed in such a way that three obstruction-pairs induce three rotational flows which result in a down-welling and a hyperbolic point in the channel cross-section. There can be a variety of micromixer geometries by arranging the mixing units in various sequences along the microchannel, and their mixing performances will differ from each other due to different flow characteristics. In this regard, numerical investigations are carried out to predict and characterize the mixing performances of various micromixers. Also experimental verifications are carried out by a flow visualization technique using phenolphthalein and sodium hydroxide solutions in a polydimethylsiloxane-based micromixer.

Park, Jang Min; Duck Seo, Kyoung; Kwon, Tai Hun

2010-01-01

82

A barrier embedded Kenics micromixer  

NASA Astrophysics Data System (ADS)

It is of great interest to enhance the mixing performance in a microchannel in which the flow is usually characterized by a low Reynolds number (Re) so that good mixing is quite difficult to achieve. In this regard, we present a new chaotic passive micromixer, named the barrier embedded Kenics micromixer (BEKM). In the BEKM, a higher level of chaotic mixing can be achieved by combining two general chaotic mixing mechanisms: splitting/reorientation and stretching/folding. The splitting/reorientation mechanism is obtained by the alternating arrangement of helical elements in the original Kenics mixer design. The stretching/folding mechanism is induced by periodic perturbation of the velocity field due to periodically inserted barriers along the cylinder wall while a relative helical flow is maintained by a helical element inside the pipe. In this study, the fully three-dimensional geometry of the BEKM was realized by micro-stereolithography, along with the Kenics micromixer and a circular T-pipe. Mixing performance was experimentally characterized in terms of an average mixing intensity via colour change of phenolphthalein. Experimental results show that the BEKM has better mixing performance than two other micromixers. The chaotic mixing mechanism proposed in this study could be applied to integrated microfluidic systems, such as the micro-total-analysis system, lab-on-a-chip and so on, as a mixing component.

Kim, Dong Sung; Lee, In Hwan; Kwon, Tai Hun; Cho, Dong-Woo

2004-10-01

83

A barrier embedded chaotic micromixer  

NASA Astrophysics Data System (ADS)

Mixing enhancement has drawn a great attention to designing of micromixers, since the flow in a microchannel is usually characterized by a low Reynolds number (Re) which makes mixing quite a difficult task to complete. In this regard, we present a new chaotic passive micromixer, called a barrier embedded micromixer (BEM). In the BEM, chaotic flow is induced by periodic perturbation of the velocity field due to periodically inserted barriers along the top surface of the channel while a helical type of flow is obtained by slanted grooves on the bottom surface in the pressure driven flow. A T-channel and a microchannel with only slanted grooves were fabricated for the purpose of experimental comparison. Mixing performance has been experimentally characterized in two ways: (i) change of average mixing intensity by means of phenolphthalein and (ii) mixing patterns via a confocal microscope. Experimental results showed that BEM has better mixing performance than the other two. A characteristic required mixing length, defined in view of intensity change, increases logarithmically with Re in BEM. The confocal microscope images indicated that BEM could achieve almost complete mixing. The chaotic mixing mechanism, proposed in this study can be easily applied to integrated microfluidic systems, such as micro-total-analysis-systems, lab-on-a-chip and so on.

Kim, Dong Sung; Lee, Seok Woo; Kwon, Tai Hun; Lee, Seung S.

2004-06-01

84

Polymeric redox-responsive delivery systems bearing ammonium salts cross-linked via disulfides  

PubMed Central

Summary A redox-responsive polycationic system was synthesized via copolymerization of N,N-diethylacrylamide (DEAAm) and 2-(dimethylamino)ethyl methacrylate (DMAEMA). N,N’-bis(4-chlorobutanoyl)cystamine was used as disulfide-containing cross-linker to form networks by the quaternization of tertiary amine groups. The insoluble cationic hydrogels become soluble by reduction of disulfide to mercaptanes by use of dithiothreitol (DTT), tris(2-carboxyethyl)phosphine (TCEP) or cysteamine, respectively. The soluble polymeric system can be cross-linked again by using oxygen or hydrogen peroxide under basic conditions. The redox-responsive polymer networks can be used for molecular inclusion and controlled release. As an example, phenolphthalein, methylene blue and reactive orange 16 were included into the network. After treatment with DTT a release of the dye could be recognized. Physical properties of the cross-linked materials, e.g., glass transition temperature (T g), swelling behavior and cloud points (T c) were investigated. Redox-responsive behavior was further analyzed by rheological measurements.

2013-01-01

85

A Low-Cost Device for Automatic Photometric Titrations  

NASA Astrophysics Data System (ADS)

Electronics is an important topic in chemistry courses. However, the introduction of basic concepts is often difficult and the lab instruments are frequently seen as "black boxes". To address this problem, we propose the construction of a simple, low-cost (about $150 U.S.) automatic photometric titrator employing a light-emitting diode (LED) and a phototransistor. The electronic circuit can be assembled by the students themselves. The device was employed to implement a common procedure in chemical labs, making feasible the introduction of concepts related to electronics in undergraduate chemistry courses. The titrator is able to work automatically, since a feedback system permits stopping the addition of titrant solution when the end-point is achieved. With this demonstration, it can be stressed that automatic procedures can be implemented without expensive instruments. Additionally, a classical procedure becomes more attractive to the students and its importance to chemical analysis can be emphasized. The feasibility of the titrator was demonstrated by acid-base titrations of HCl solutions with NaOH in the presence of phenolphthalein and by iodimetric determination of ascorbic acid in vitamin C tablets and lemon juice. Precise results (0.7% relative standard deviation, n = 10) in agreement at the 95% confidence level with those attained by a conventional procedure were obtained.

Rocha, Fábio R. P.; Reis, Boaventura F.

2000-02-01

86

Novel approaches to analysis by flow injection gradient titration.  

PubMed

Two novel procedures for flow injection gradient titration with the use of a single stock standard solution are proposed. In the multi-point single-line (MP-SL) method the calibration graph is constructed on the basis of a set of standard solutions, which are generated in a standard reservoir and subsequently injected into the titrant. According to the single-point multi-line (SP-ML) procedure the standard solution and a sample are injected into the titrant stream from four loops of different capacities, hence four calibration graphs are able to be constructed and the analytical result is calculated on the basis of a generalized slope of these graphs. Both approaches have been tested on the example of spectrophotometric acid-base titration of hydrochloric and acetic acids with using bromothymol blue and phenolphthalein as indicators, respectively, and sodium hydroxide as a titrant. Under optimized experimental conditions the analytical results of precision less than 1.8 and 2.5% (RSD) and of accuracy less than 3.0 and 5.4% (relative error (RE)) were obtained for MP-SL and SP-ML procedures, respectively, in ranges of 0.0031-0.0631 mol L(-1) for samples of hydrochloric acid and of 0.1680-1.7600 mol L(-1) for samples of acetic acid. The feasibility of both methods was illustrated by applying them to the total acidity determination in vinegar samples with precision lower than 0.5 and 2.9% (RSD) for MP-SL and SP-ML procedures, respectively. PMID:17903467

Wójtowicz, Marzena; Kozak, Joanna; Ko?cielniak, Pawe?

2007-04-08

87

p53 induction as a genotoxic test for twenty-five chemicals undergoing in vivo carcinogenicity testing.  

PubMed Central

In vivo carcinogenicity testing is an expensive and time-consuming process, and as a result, only a relatively small fraction of new and existing chemicals has been tested in this manner. Therefore, the development and validation of alternative approaches is desirable. We previously developed a mammalian in vitro assay for genotoxicity based on the ability of cells to increase their level of the tumor-suppressor protein p53 in response to DNA damage. Cultured cells are treated with various amounts of the test substances, and at defined times following treatment, they are harvested and lysed. The lysates are analyzed for p53 by Western blot and/or enzyme-linked immunosorbent assay analysis. An increase in cellular p53 following treatment is interpreted as evidence for DNA damage. To determine the ability of this p53-induction assay to predict carcinogenicity in rodents and to compare such results with those obtained using alternate approaches, we subjected 25 chemicals from the predictive toxicology evaluation 2 list to analysis with this method. Five substances (citral, cobalt sulfate heptahydrate, D&C Yellow No. 11, oxymetholone, and t-butylhydroquinone) tested positive in this assay, and three substances (emodin, phenolphthalein, and sodium xylenesulfonate) tested as possibly positive. Comparisons between the results obtained with this assay and those obtained with the in vivo protocol, the Salmonella assay, and the Syrian hamster embryo (SHE) cell assay indicate that the p53-induction assay is an excellent predictor of the limited number of genotoxic carcinogens in this set, and that its accuracy is roughly equivalent to or better than the Salmonella and SHE assays for the complete set of chemicals. Images Figure 1 Figure 2 Figure 3 Figure 4

Duerksen-Hughes, P J; Yang, J; Ozcan, O

1999-01-01

88

Evaluating the seasonal changes of water quality of the De?irmendere and Galyan Rivers (Trabzon, Turkey).  

PubMed

The De?irmendere and Galyan (De?irmendere tributary) Rivers that discharge their water into the Black Sea are important watersheds in the northeastern part of Turkey. Water quality parameters were sampled from 1997 through 2001 for each year at five sites (three for Galyan, two for Degirmendere) along 29 and 42 km gradients, respectively covering all seasons. Surface water was collected from the sites and analyzed for temperature, total alkaline (MAAL), total dissolved solids (TDS), dissolved oxygen (DO), pH, conductivity (EC), nitrate (NO3), nitrite (NO2), total hardness (TH), phenolphthalein alkalinities (PAL) and organic matter (PV). Seasonal changes of water quality were analyzed statistically for both Rivers and evaluated according to the TS 266, EU and WHO standards. The analysis of variance results showed that Ca, Mg, MAL, NO3, pH, TDS and TH parameters of the De?irmendere River and Ca, DO, EC, MAL, NO3, pH and TH parameters of the Galyan River showed seasonal differences (p<0.05). The maximum values of the water pollution parameters for the two Rivers were below the threshold values throughout the study period. When both Rivers were compared, the mean values of the pollution parameters of the Degirmendere River were higher than those of the Galyan River and very close the limits. The results indicate that both Rivers can be used for the production of potable water during all seasons but only with an advanced treatment in the De?irmendere and a moderate treatment in the Galyan River, and for indirect and non-contact recreational activities. PMID:15248656

Altun, Lokman; Yilmaz, Murat; Acar, Cengiz; Turna, Ibrahim; Ba?kent, E Zeki; Bilgili, Ertu?rul

2003-10-01

89

Measurements of Molecular Mixing in a High Schmidt Number Rayleigh-Taylor Mixing Layer  

SciTech Connect

Molecular mixing measurements are performed for a high Schmidt number (Sc {approx} 10{sup 3}), small Atwood number (A {approx} 7.5 x 10{sup -4}) buoyancy-driven turbulent Rayleigh-Taylor mixing layer in a water channel facility. Salt was added to the top stream to create the desired density difference. The degree of molecular mixing was measured as a function of time by monitoring a diffusion-limited chemical reaction between the two fluid streams. The pH of each stream was modified by the addition of acid or alkali such that a local neutralization reaction occurred as the two fluids molecularly mixed. The progress of this neutralization reaction was tracked by the addition of phenolphthalein - a pH-sensitive chemical indicator - to the acidic stream. Accurately calibrated backlit optical techniques were used to measure the average concentration of the colored chemical indicator. Comparisons of chemical product formation for pre-transitional buoyancy- and shear-driven mixing layers are given. It is also shown that experiments performed at different equivalence ratios (acid/alkali concentration) can be combined to obtain a mathematical relationship between the colored product formed and the density variance. This relationship was used to obtain high-fidelity, quantitative measures of the degree of molecular mixing which are independent of probe resolution constraints. The dependence of such mixing parameters on the Schmidt and Reynolds numbers is examined by comparing the current Sc {approx} 10{sup 3} measurements with Sc = 0.7 gas-phase and Pr = 7 liquid-phase measurements. This comparison indicates that the Schmidt number has a large effect on the bulk quantity of mixed fluid at small Reynolds numbers Re{sub h} < 10{sup 3}. At late times, all mixing parameters indicated a greater degree of molecular mixing and a decreased Schmidt number dependence. Implications for the development and quantitative assessment of turbulent transport and mixing models appropriate for Rayleigh?Taylor instability-induced mixing are discussed.

Mueschke, N J; Schilling, O; Youngs, D L; Andrews, M

2007-12-03

90

Effect of galactosamine-induced hepatic UDP-glucuronic acid depletion on acetaminophen elimination in rats. Dispositional differences between hepatically and extrahepatically formed glucuronides of acetaminophen and other chemicals.  

PubMed

Galactosamine (GAL) markedly depletes hepatic UDP-glucuronic acid (UDP-GA) whereas extrahepatic UDP-GA is minimally affected. This suggests that GAL predominantly inhibits hepatic glucuronidation. Therefore, the effect of GAL-induced hepatic UDP-GA depletion was examined in bile duct-cannulated rats to determine the role of hepatic glucuronidation in the disposition of acetaminophen (AA). GAL markedly altered the fate of AA-glucuronide but had little or no effect upon other AA metabolites. GAL decreased the biliary excretion of AA-glucuronide up to 92%, whereas reductions in blood levels and urinary excretion of AA-glucuronide did not exceed 50%. This suggests that AA-glucuronide excreted in bile is predominantly of hepatic origin whereas AA-glucuronide found in blood and urine is derived from both hepatic and extrahepatic tissues. Data in the present and previous studies [Gregus, Watkins, Thompson, Klaassen: J. Pharmacol. Exp. Ther. 225, 256, (1983)] indicate that GAL greatly reduced the biliary excretion of AA- and valproic acid-glucuronide whereas the biliary excretion of the glucuronides of phenolphthalein, iopanoic acid, bilirubin, and diethylstilbestrol was only partially decreased. This difference appears to be largely due to differential contributions by the liver and extrahepatic tissues in the glucuronidation of various compounds as well as the availability of glucuronides formed in extrahepatic tissues for biliary excretion. Specifically, the extrahepatically formed glucuronide conjugates of AA and valproic acid are not readily available for biliary excretion whereas the glucuronides of the other compounds are readily excreted into bile.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2903018

Gregus, Z; Madhu, C; Goon, D; Klaassen, C D

91

Study of dynamics and crystallization kinetics of 5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile at ambient and elevated pressure  

NASA Astrophysics Data System (ADS)

The organic liquid ROY, i.e., 5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile, has been a subject of detailed study in the last few years. One interest in ROY lies in its polymorph-dependent fast crystal growth mode below and above the glass transition temperature. This growth mode is not diffusion controlled, and the possibility that it is enabled by secondary relaxation had been suggested. However, a previous study by dielectric relaxation spectroscopy had not been able to find any resolved secondary relaxation. The present paper reports new dielectric measurements of ROY in the liquid and glassy states at ambient pressure and elevated pressure, which were performed to provide more insight into the molecular dynamics as well as the crystallization tendency of ROY. In the search of secondary relaxation, a special glassy state of ROY was prepared by applying high pressure to the liquid state, from which secondary relaxation was possibly resolved. Thus, the role of secondary relaxation in crystallization of ROY remains to be clarified. Notwithstanding, the secondary relaxation present is not necessarily the sole enabler of crystallization. In an effort to search for possible cause of crystallization other than secondary relaxation, we also performed crystallization kinetics studies of ROY at different T and P combinations while keeping the structural relaxation time constant. The results show that crystallization of ROY speeds up with pressure, opposite to the trend found in the crystallization of ibuprofen studied up to 1 GPa. The dielectric relaxation and thermodynamic properties of ROY with phenolphthalein dimethylether (PDE) are similar in many respects, but PDE does not crystallize. Taking all the above into account, besides the secondary relaxation, the specific chemical structure, molecular interactions and packing of the molecules are additional factors that could affect the kinetics of crystallization found in ROY.

Adrjanowicz, K.; Kaminski, K.; Paluch, M.; Ngai, K. L.; Yu, Lian

2012-06-01

92

COMPACT and molecular structure in toxicity assessment: a prospective evaluation of 30 chemicals currently being tested for rodent carcinogenicity by the NCI/NTP.  

PubMed Central

A new series of 30 miscellaneous National Toxicology Program chemicals has been evaluated prospectively for carcinogenicity and overt toxicity by COMPACT (Computer Optimised Molecular Parametric Analysis for Chemical Toxicity. CYP1A and CYP2E1). Evaluations were also made by Hazardexpert, and for metal ion redox potentials; and these, together with COMPACT, were compared with results from the Ames test for mutagenicity in Salmonella, the micronucleus test, and 90-day subchronic rodent pathology. Seven of the 30 chemicals (nitromethane, chloroprene, xylenesulphonic acid, furfuryl alcohol, anthraquinone, emodin, cinnamaldehyde) were positive for potential carcinogenicity in the COMPACT evaluation; xylenesulphonic acid and furfuryl alcohol were only equivocally positive. Four of the 30 chemicals-scopolamine, D&C Yellow No. 11, citral, cinnamaldehyde-were positive by Hazardexpert; 6 of 30-D&C Yellow No. 11, 1-chloro-2-propanol, anthraquinone, emodin, sodium nitrite, cinnamaldehyde-were positive in the Ames test; 2 of 30-phenolphthalein and emodin-were positive in the in vivo cytogenetics test; and 3 of 30-molybdenum trioxide, gallium arsenide, vanadium pentoxide-were metal compounds with redox potentials of the metal/metal ion indicative of possible carcinogenicity. The overall prediction for carcinogenicity was positive for 12 of 30 chemicals: nitromethane, chloroprene, D&C Yellow No. 11, molybdenum trioxide, 1-chloro-2-propanol, furfuryl alcohol, gallium arsenide, anthraquinone, emodin, sodium nitrite, cinnamaldehyde, vanadium pentoxide). This overall prediction has been made on the basis of the results of the computer tests and from consideration of the information from bacterial mutagenicity, together with likely lipid solubility and pathways of metabolism and elimination.

Lewis, D F; Ioannides, C; Parke, D V

1996-01-01

93

Design and characterization of a passive recycle micromixer  

NASA Astrophysics Data System (ADS)

A new design was devised for a recycle micromixer, i.e., a passive micromixer with side channels for a recycle flow. The geometry, required to perform a recycle flow and effective mixing, was determined by a simulation based on computational fluid dynamics. A recycle flow of the mixed flow of each unit was introduced to the inlet flow, and a circular flow was generated in the body of the mixer. For complete mixing, five units of the micromixer were connected in series. The simulations were performed at Reynolds numbers of 7, 14 and 28 and channel depths of 100, 150 and 200 µm. Mixing efficiency and direction of recycle flow were significantly affected by both Re and channel depth. When channel depth was 150 µm, mixing efficiency of the micromixer increased from 89.3 to 95.6, 98.4 and 98.6% with the increase of Re from 7 to 14, 28 and 42, respectively. The increasing channel depth also increased mixing efficiency. The micromixer was fabricated by a conventional photolithography technique using polydimethylsiloxane. Color dispersion in blue ink was compared with simulated flow patterns. The characterization of mixing in the recycle micromixer was verified by using an aqueous NaOH solution and phenolphthalein solution, composed of the same volume of ethanol and water. For both cases, fully mixed profiles were achieved along five micromixers, connected in a series at a flow rate of 0.1 ml min-1 for each flow and a short residence time of 0.11 s.

Jeon, Min Ku; Kim, Joon-Ho; Noh, Jermim; Kim, Soo Ho; Park, Hyun Gyu; Woo, Seong Ihl

2005-02-01

94

Characterization of human liver enzymes involved in the biotransformation of boceprevir, a hepatitis C virus protease inhibitor.  

PubMed

Boceprevir (SCH 503034), a protease inhibitor, is under clinical development for the treatment of human hepatitis C virus infections. In human liver microsomes, formation of oxidative metabolites after incubations with [(14)C]boceprevir was catalyzed by CYP3A4 and CYP3A5. In addition, the highest turnover was observed in recombinant CYP3A4 and CYP3A5. After a single radiolabeled dose to human, boceprevir was subjected to two distinct pathways, namely cytochrome P450-mediated oxidation and ketone reduction. Therefore, attempts were made to identify the enzymes responsible for the formation of carbonyl-reduced metabolites. Human liver S9 and cytosol converted ? 28 and ? 68% of boceprevir to M28, respectively, in the presence of an NADPH-generating system. Screening of boceprevir with recombinant human aldo-keto reductases (AKRs) revealed that AKR1C2 and AKR1C3 exhibited catalytic activity with respect to the formation of M+2 metabolites (M28 and M31). The formation of M28 was inhibited by 100 ?M flufenamic acid (80.3%), 200 ?M mefenamic acid (83.7%), and 100 ?M phenolphthalein (86.1%), known inhibitors of AKRs, suggesting its formation through carbonyl reduction pathway. Formation of M28 was also inhibited by 100 ?M diazepam (75.1%), 1 mM ibuprofen (70%), and 200 ?M diflunisal (89.4%). These data demonstrated that CYP3A4 and CYP3A5 are primarily responsible for the formation of oxidative metabolites and the formation of M28 and M31, the keto-reduced metabolites, are most likely mediated by AKR1C2 and AKR1C3. Because the biotransformation and clearance of boceprevir involves two different enzymatic pathways, boceprevir is less likely to be a victim of significant drug-drug interaction with concomitant medication affecting either of these pathways. PMID:21123164

Ghosal, Anima; Yuan, Yuan; Tong, Wei; Su, Ai-Duen; Gu, Chunyan; Chowdhury, Swapan K; Kishnani, Narendra S; Alton, Kevin B

2010-12-01

95

Modified starch enhances absorption and accelerates recovery in experimental diarrhea in rats.  

PubMed

Rice gruels have been used as home remedies to treat dehydration associated with diarrheal illness in developing countries. These preparations have produced conflicting results, most likely due to the heterogeneity of starch used. We investigated whether the modified tapioca starch, Textra (TX), at 5.0 or 10.0 g/L added to a 90 mmol/L Na+-111 mmol glucose oral rehydration solution (ORS) enhanced water and electrolyte absorption in two models of diarrhea. To induce a secretory state (model A), the jejunum of juvenile rats was perfused with 10 mmol/L theophylline (THEO) under anesthesia and then perfused with the solutions indicated above. To produce chronic osmotic-secretory diarrhea (model B), rats had a magnesium citrate-phenolphthalein solution as the sole fluid source for 1 wk, and then were perfused as the THEO-treated rats. Water, electrolyte, and glucose absorption were measured during both perfusions. As an extension of the perfusion studies, we compared how fast rats recovered from chronic osmotic diarrhea by offering them either water, ORS, or ORS containing 5.0 g/L TX along with solid food. Recovery rate markers were measured after 24 h and included weight gain, food and fluid intake, and stool output. In model A, addition of 5.0 g/L TX to ORS reversed Na+ secretion and improved net water as well as K+ and glucose absorption, compared with THEO-treated rats perfused with ORS without TX. In model B, addition of TX to ORS increased water, Na+, K+, and glucose absorption, compared with rats perfused without TX. Increasing TX from 5.0 to 10.0 g/L had no additional benefit. In recovery experiments, animals with free access to ORS with TX had significantly greater weight gain and decreased stool output compared with animals recovering with water or ORS without TX. Our experiments suggest that TX may be a useful additive to standard ORS to promote fluid and electrolyte absorption and may provide additional energy without increasing ORS osmotic load. PMID:10088661

Wingertzahn, M A; Teichberg, S; Wapnir, R A

1999-03-01

96

Application of experimental and numerical simulation techniques to microscale devices  

NASA Astrophysics Data System (ADS)

Two of the areas that have become relevant recently are the areas of mixing in micro-scale devices, and manufacturing of functional nanoparticles. MicroPIV experiments were performed on two different mixers, one a wide microchannel with the surface grooves, in the laminar regime, and the other, a confined impinging jets reactor, in the laminar and turbulent regimes. In the wide microchannel with surface grooves, microPIV data were collected at the interface and the midplane at the Reynolds numbers of 0.08, 0.8, and 8. The experiments were performed on three internal angles of the chevrons, namely 135°, 90°, and 45°. The normalized transverse velocity generated in the midplane due to the presence of the grooves, is the strongest for the internal angle of 135°, and in that, the normalized transverse velocity is maximum at the Reynolds numbers of 0.08 and 0.8. MicroPIV experiments were performed in a confined impinging jets reactors at Reynolds numbers of 200, 1000, and 1500. The data was collected in the midplane, and turbulent statistics were further computed. The high velocity jets impinge along the centerline of the reactor. Upon impinging, part of the fluid turns towards the top wall and the majority of it turn towards the outlet. This high velocity impingement causes and unstable zone called the impingement zone, which moves about the centerline line, causing the jets to flap back and forth. Spatial correlations were computed to get an estimate of the size of the coherent structures. Large eddy simulation was performed on the CIJR for the Reynolds numbers of 1000 and 1500, using OpenFOAM. The Reynolds number is based on the inlet jet hydraulic diameter. Excellent agreement was found with the experimental and simulation data. Turbulent reactive mixing in a rectangular microscale confined impinging-jets reactor (CIJR) was investigated using the pH indicator phenolphthalein in this study for three different jet Reynolds numbers of 25, 1000 and 1500. Laminar flow regime was observed at Reynolds number of 25 whereas the flow was turbulent at Reynolds numbers of 1000 and 1500. An image processing technique was applied to instantaneous images to extract quantitative mixing data by identifying regions with pH ? 9.3 and regions with pH < 9.3. The ensemble-averages were computed using these thresholded images to compare mixing performance between different Reynolds numbers. Finally, the spatial auto-correlation fields of the thresholded images fluctuations were evaluated, based on which large-scale turbulent structure were analyzed.

Somashekar, Vishwanath

97

Chemical enhancement techniques of bloodstain patterns and DNA recovery after fire exposure.  

PubMed

It is common in forensic casework to encounter situations where the suspect has set a fire to cover up or destroy possible evidence. While bloodstain pattern interpretation, chemical enhancement of blood, and recovery of deoxyribonucleic acid (DNA) from bloodstains is well documented in the literature, very little information is known about the effects of heat or fire on these types of examinations. In this study, a variety of known types of bloodstain patterns were created in a four-room structure containing typical household objects and furnishings. The structure was allowed to burn to flashover and then it was extinguished by firefighters using water. Once the structure cooled over night, the interior was examined using a bright light. The bloodstains were evaluated to see if the heat or fire had caused any changes to the patterns that would inhibit interpretation. Bloodstain patterns remained visible and intact inside the structure and on furnishings unless the surface that held the blood was totally burned away. Additionally, a variety of chemical techniques were utilized to better visualize the patterns and determine the possible presence of blood after the fire. The soot from the fire formed a physical barrier that initially interfered with chemical enhancement of blood. However, when the soot was removed using water or alcohol, the chemicals used, fluorescein, luminol, Bluestar, and Hemastix, performed adequately in most of the tests. Prior to DNA testing, the combined phenolphthalein/tetramethyl benzidine presumptive test for the presence of blood was conducted in the laboratory on samples recovered from the structure in an effort to assess the effectiveness of using this type of testing as a screening tool. Test results demonstrated that reliance on obtaining a positive presumptive result for blood before proceeding with DNA testing could result in the failure to obtain useful typing results. Finally, two DNA recovery methods (swabbing the stain plus cutting or scraping the stain) were attempted to evaluate their performance in recovering samples in an arson investigation. Recovery of DNA was more successful in some instances with the swabbing method, and in other instances with the cutting/scraping method. Therefore, it is recommended that both methods be used. For the most part, the recovered DNA seemed to be unaffected by the heat, until the temperature was 800 degrees C or greater. At this temperature, no DNA profiles were obtained. PMID:19018938

Tontarski, Karolyn L; Hoskins, Kyle A; Watkins, Tani G; Brun-Conti, Leanora; Michaud, Amy L

2008-11-06

98

Self-Irradiation Effects on 99Mo Reagents and Products  

SciTech Connect

produced in 1996 and shipped to pharmaceutical houses for evaluation of compatibility with oxime solution used to precipitate `?vfo as the oxime complex is both air and light-sensitive, and containing a black precipitate that forms during shipment, presumably as a result of self- irradiation. Addition of sodium hypochlorite to the product solution prior to shipment prevents precipitate formation, indicating the precipitate is a reduced form of `%lo. to remove any precipitate. Duplicate aliquots of the filtered samples were titrated to a phenolphthalein irradiation and afler standing at room temperature for 86.4 hours. Precipitates were washed to a FTIR analysis of the white precipitate showed it to be alpha benzoin oxime. Since the basic After 86.4 hours, no precipitate had formed in bottles containing sodium hypochlorite. Black precipitate had formed in all bottles that did not contain sodium hypochlorite after 14.4 hours. The precipitate appeared to initially form on the surface of the HDPE sample bottles and Black precipitate was first noticed in sample set 1 after 28.8 hrs' irradiation. No visible sample containing precipitate was kept at room temperature in the original bottle. Precipitate in sample sets 2 and 3. Since no precipitate formed in these bottles, this was equivalent to duplicate samples. Once the precipitate in the 20-mL aliquots that had been set aside had returned to sample sets 1 through 3 and the samples with redissolved precipitate all experienced an average decrease in base strength of 0.013 meq mL-l. Sample 1-C had a decrease of 0.004 meq mL-l and sample 1-D had returned to the initial value of 0.198 meq mL-l. Raman spectra for the black precipitate from samples l-C, 1-D and supplemental sample set 1 Fig. 2. Raman spectra of the black precipitate formed in 9%40 product solutions after 28.8,43.2, 72 and 86.4 hours of `oCo irradiation in Sandia's Gamma Irradiation Facility. increase with time, as seen in the titration of 1-C and 1-D samples. The precipitate does not expect to see precipitate in the glass bottles. The fact that no precipitate is observed when the no precipitate is observed in a glass container is an indication that the rates of molybdenum that precipitate does not form when the solution is in a glass bottle. A hydrogen source other

Carson, S.D.; Garcia, M.J.; McDonald, M.J.; Simpson, R.L.; Tallant, D.R.

1998-10-07

99

Improved water and sodium absorption from oral rehydration solutions based on rice syrup in a rat model of osmotic diarrhea.  

PubMed

Rice syrup solids, rice protein, and casein hydrolysate were added to experimental oral rehydration solutions in various combinations and tested in a rat intestinal perfusion system. Chronic osmotic diarrhea was induced in juvenile rats by supplying the cathartic agents, magnesium citrate and phenolphthalein, in their drinking water for 1 week. The experimental oral rehydration solutions were compared with standard oral rehydration solutions containing 20 gm/L or 30 gm/L of glucose and with each other to determine if there were significant differences in net water, sodium, or potassium absorption. An oral rehydration solution containing 30 gm/L of rice syrup solids had a net water absorption rate significantly higher than that of the standard 20 gm/L glucose-based oral rehydration solution (2.1 +/- 0.62 versus 1.5 +/- 0.48 microliters/[min x cm], p less than 0.05). Casein hydrolysate did not significantly affect net water absorption. However, combinations of 30 gm/L rice syrup solids and 5 gm/L casein hydrolysate significantly increased (p less than 0.05) net sodium and potassium absorption compared with the 20 gm/L glucose-based oral rehydration solution but not versus rice syrup solids alone. Oral rehydration solutions containing 30 gm/L rice syrup solids plus 5 gm/L rice protein, and 30 gm/L rice syrup solids plus 5 gm/L casein hydrolysate, had net water absorption rates significantly higher than the rate of a 30 gm/L glucose-based oral rehydration solution (2.5 +/- 0.36 and 2.4 +/- 0.38, respectively, versus 0.87 +/- 0.40 microliters/[min x cm], p less than 0.05). Rice protein and casein hydrolysate, however, did not significantly affect net water, sodium, or potassium absorption when added to rice protein glucose-based oral rehydration solutions. An inverse correlation between osmolality and net water absorption was observed (r = -0.653, p less than 0.02). The data suggest that substitution of rice syrup solids for glucose in oral rehydration solutions will improve water absorption and that rice syrup solids in combination with protein hydrolysates may, in addition, promote better sodium and potassium uptake. PMID:2007957

Wapnir, R A; Litov, R E; Zdanowicz, M M; Lifshitz, F

1991-04-01

100

ORGANIC MATTER IN THE EXPIRED BREATH WITH ESPECIAL REFERENCE TO ITS INHIBITING POWER ON OXIDIZING FERMENTS.  

PubMed

Weichardt claims to have demonstrated the presence of an organic body in the expired air. He allowed the exhaled breath to pass through hydrochloric acid solution, evaporated the resulting solution to dryness on a water bath, and obtained a weighable residue which charred on ignition. If he neutralized the acid solution and concentrated it under reduced pressure, he obtained a solution which inhibited the bluing of the guaiacum indicator by blood. By exposing calcium chloride in a room in which the air had been vitiated, he claimed also to have obtained a substance from the air which prevented the bluing of the guaiacum indicator by blood. The experiments here recorded show that a variable amount of matter is retained by weak hydrochloric solution when exhaled breath is passed through it, and that this matter is volatile on ignition. Contrary to the findings of Weichardt, there is no charring or blackening. Nesslerization shows the residue to consist mainly, if not wholly, of ammonium chloride. This ammonia is believed to have come from the decomposition of food particles about the teeth. In one case the person (S.) had smoked just before the experiment, so that a small amount of the ammonia from the tobacco smoke may have been held temporarily by the saliva and food particles in the mouth and been given off gradually during the experiment. Weichardt's experiments on the inhibition of the guaiacum test for blood by means of the substances retained when exhaled breath is passed through hydrochloric acid or over calcium chloride crystals are not corroborated. It is further shown that the guaiacum indicator is unreliable for these tests in view of the fact that a small amount of free acid or free alkali will inhibit the guaiacum test for blood. This fact is offered as a probable explanation of Weichardt's results. Calcium chloride alone gives a deep blue color with the guaiacin indicator. Weichardt used this salt to collect from the expired breath certain unknown substances which he claims inhibit the oxidation of guaiacum by blood. His results are therefore inconclusive. The phenolphthalin test for blood has been studied in this connection and further light has been thrown on this reaction. The sodium salt of phenolphthalin is colorless in alkaline solution, and is readily oxidized by minute quantities of blood to phenolphthalein which gives a characteristic deep purplish red color in alkaline solution. It has been found that the presence of calcium chloride and ammonium chloride in small amounts retards and, in large amounts, prevents this reaction. It is believed that any salt composed of a weak base combined with a strong acid will have the same effect. This is discussed in the text. It has also been shown that the presence of calcium chloride or ammonium chloride decreases the depth of color of phenolphthalein in sodium hydroxide solution. Carbon dioxide also prevents the oxidation of phenolphthalin by blood. Of course this does not mean that carbon dioxide prevents the action of the oxidizing ferments generally. In this particular case the substance to be oxidized, namely phenolphthalin, was not allowed by reason of the presence of the carbon dioxide to combine with the alkali and thereby assume a state in which it could be easily oxidized. The results of one experiment seem to indicate a relation between the amount of dissolved oxygen in the solutions and the percentage of oxidation. Sodium chloride either alone or with the aid of hydrogen peroxide is able to bring about the oxidation of phenolphthalin in alkali to a very slight extent (3.5 to 5 per cent. in twenty-four hours). Therefore phenolphthalin as a test for oxidizing ferments should not be used in the presence of an appreciable amount of inorganic salts or carbon dioxide. Complete dialysis is recommended in these cases. It is also to be noted that the great delicacy of the test allows considerable dilution. Liquids were obtained from the expired breath by passing this through weak hydrochloric acid or by condensing the moisture in it by conducting it through

Amoss, H L

1913-02-01