scholarly journals A SCHIFF REAGENT OF CALIBRATED SENSITIVITY

1959 ◽  
Vol 7 (2) ◽  
pp. 93-97 ◽  
Author(s):  
HERBERT ELFTMAN
Keyword(s):  
Sulfur Dioxide ◽  
Positive Response ◽  
Spectrophotometric Analysis ◽  
Sulfurous Acid ◽  
Low Concentrations ◽  
Red Color ◽  
Violet Color ◽  
Schiff Reagent ◽  
The One ◽  
Excess Sulfur

The sensitivity of Schiff reagent for the detection of low concentrations of aldehyde increases progressively as the concentration of sulfurous acid in the reagent is lowered. Calibration of sensitivity is readily accomplished by titrating the Schiff reagent against the iodine of Lugol's solution. Stability of Schiff's solution depends on decreasing the evaporation of sulfur dioxide and of retarding the change of sulfite to sulfate. For practical purposes these ends can be achieved by storage in the refrigerator of a solution with greater sulfurous acid content and acidity than the solution used for staining. Evacuation of the excess sulfur dioxide or mixing in proper proportions with used reagent allows the rapid production of a solution of the desired sensitivity. If chemical preservatives are required, 0.5% hydroquinone gives very good results. Spectrophotometric measurement of the colored solutions produced by adding aldehyde to Schiff reagent indicates that at least two distinct compounds may result. The one that is usually mentioned as characteristic of a positive response of aldehyde to the Schiff reagent has a violet color. When the concentration of aldehyde is so low that only a Schiff solution of low sulfurous acid titer will react with it, a red color is produced. Spectrophotometric analysis shows this compound to be different from the original basic fuchsin and validates its use as an endpoint in the reaction of aldehyde with Schiff's reagent.

Sulfurous Acid Corrosion of Low Carbon Steel at Ordinary Temperatures - I. Its Nature

CORROSION ◽  
1966 ◽  
Vol 22 (5) ◽  
pp. 143-146 ◽  
Author(s):  
W. McLEOD ◽  
R. R. ROGERS
Keyword(s):  
Water Vapor ◽  
Carbon Steel ◽  
Sulfur Dioxide ◽  
Corrosion Rate ◽  
Acid Corrosion ◽  
Low Carbon Steel ◽  
Rate Data ◽  
Low Carbon ◽  
Sulfurous Acid ◽  
Ordinary Temperature

Abstract Corrosion rate data are presented for low carbon steel in (1) a combination of sulfur dioxide, water vapor and air, and (2) aqueous solutions of sulfurous acid in the absence of air, at ordinary temperature. Information as to the nature of the corrosion products is presented and it is shown that this depends on the place in which the corrosion takes place to an important extent.

scholarly journals EFEKTIVITAS MEDIA PERMAINAN SUDOKU DALAM MENGHAFAL HURUF KANA (Menggunakan Metode Eksperimen Quasi Terhadap Siswa Japanese Club SMP Laboratorium Percontohan UPI)

2016 ◽  
Vol 1 (3) ◽  
pp. 35
Author(s):  
Konstantina Adinda Putrilani ◽  
Renariah Renariah ◽  
Neneng Sutjiati
Keyword(s):  
Data Analysis ◽  
Positive Response ◽  
Experiment Design ◽  
Writing System ◽  
Significance Level ◽  
Experiment Method ◽  
Before And After ◽  
Post Test ◽  
The Media ◽  
The One

Ketika mempelajari bahasa Jepang di sekolah, aspek dasar yang harus dipelajari siswa adalah huruf Jepang. Dalam sistem penulisan, bahasa Jepang memiliki empat huruf, yaitu huruf kanji, hiragana, katakana, dan roomaji. Tetapi sebelum tahap belajar huruf kanji, terlebih dahulu siswa mempelajari huruf hiragana dan katakana yang biasa disebut huruf kana. Huruf kana terdiri atas 96 huruf dimana huruf hiragana dan huruf katakana tersebut bentuknya mirip. Hal ini menyebabkan siswa kesulitan untuk mempelajari huruf kana. Oleh karena itu, diperlukan suatu media untuk mempermudah pembelajar mempelajari huruf kana. Salah satu media yang dapat digunakan adalah media permainan. Dalam penelitian ini, media permainan yang digunakan adalah media permainan sudoku yang sudah di modifikasi. Tujuan dari penelitian ini adalah untuk mengetahui kemampuan siswa dalam pembelajaran huruf kana, sebelum dan sesudah menggunakan media permainan sudoku. Selain itu, penelitian ini bertujuan untuk menganalisis pengaruh penggunaan media permainan sudoku terhadap pembelajaran huruf kana, dan untuk mengetahui respon siswa terhadap penggunaan media permainan sudoku. Penelitian ini menggunakan metode experimen quasi dengan desain eksperimen yaitu one group pre-test - post-test. Sampel penelitian adalah anggota Japanese Club sebanyak 20 orang yang diambil dari populasi SMP Laboratorium Percontohan UPI Bandung. Instrumen yang digunakan adalah tes, angket dan obsevasi. Berdasarkan hasil analisis data, nilai t hitung sebesar 6.53. Nilai t tabel sebesar 2.09 pada taraf signifikansi 5% dan 2.86 pada taraf signifikansi 1%. Dengan demikian, diperoleh hasil t hitung lebih besar dibandingkan nilai t tabel pada taraf signifikansi 5% (6.53 > 2.09). Hal ini menunjukkan bahwa pengguanaan media permainan sudoku dalam pembelajaran huruf kana sangat efektif. Selain itu, berdasarkan hasil analisis data angket, responden memberikan tanggapan yang positif terhadap penggunaan media permainan sudoku yaitu menarik, dan mudah diikuti. When studying Japanese at school, basic aspects must study is the Japanese letter. In its writing system, Japanese has four letters, namely kanji, hiragana, katakana, and roomaji. Before the stage of kanji learning, firstly, students have to learn hiragana and katakana which are commonly called kana. Kana, composed of 96 letters where the letter of the hiragana and katakana are barely different. This causes difficulties for students to learn kana. Therefore, we need a media to facilitate learners to learn kana. One medium that can be used are game as the learning media. This study, the media used is a sudoku game that has been modified. The purpose of this study is to acknowledge students’ ability in learning kana, before and after using the sudoku game as a media. In addition, this study also aims to analyze the influence of sudoku game usage as the media in learning kana Letters, and to find out the students' response to the use of sudoku game as a media. This study uses a quasi experiment method with the one group pre-test - post-test as experiment design. Samples were 20 students from Japanese Club members who were taken from a population of SMP Laboratorum Percontohan UPI Bandung. The instrument used was test, questionnaire and observation. Based on the data analysis, the t value at 6.53. T table at 2.09 on a significance level of 5% and 2.86 at 1% significance level. Thus, the results obtained that t value is greater than t table at a significance level of 5% (6.53> 2.09). This shows that the usage of sudoku game as media is a very effective in learning kana. In addition, based on data analysis of the questionnaire, the respondents gave a positive response to the use of media sudoku game that are attractive, and easy to follow

scholarly journals The Structural Characteristics of Chicken Fibrinogen

1977 ◽  
Author(s):  
J. Pindyck ◽  
M. W. Mosesson ◽  
D. Bannerjee ◽  
D. Galanakis
Keyword(s):  
Gel Electrophoresis ◽  
Structural Characteristics ◽  
Periodic Acid ◽  
Factor Xiiia ◽  
Periodic Acid Schiff ◽  
Polymer Formation ◽  
Sensitive Site ◽  
Schiff Reagent ◽  
The One ◽  
Fibrinogen Molecule

The structure and subunit composition of chicken fibrinogen(ϕ) have been investigated. Dodecyl sulfate gel electrophoresis of unreduced specimens revealed a single ϕ band with a molecular weight of approximately 320,000. ϕ and fibrin specimens were also electrophoresed after reduction with dithiothreitol, and after crosslinking of unreduced specimens in the presence of Factor Xllla. Chromatographically separated S-sulfo chains were also studied after reptilase or thrombin treatment,and certain samples were stained with periodic acid Schiff reagent(PAS). Chicken Aα chains weresmaller than human Aα chains (54,500 vs.70,900, respectively) but, like mammalian Aα chains, they possessed a reptilase and thrombin sensitive site, were PAS negative,and undergo Factor XIIIa catalyzed α-polymer formation. The sizes of chicken Bβ and γ chains were nearly thesame as their mammalian counterparts, (i. e. 60,000 and 49,000 respectively) ; both types of chains were PAS positive. Chicken Bβ chains possessed a slowly reactive thrombin sensitive site apparently corresponding to the one in human ϕ; the chicken β chains, like mammalian β chains, did not undergo Factor XIIIa catalyzed cross-linking. Like mammalian γ chains, chicken γ chains could undergo Factor XIIIa catalyzed γ-γ dimerization and did not possess thrombin or reptilase sensitive sites. These findings indicate that the chicken fibrinogen molecule is composed of three pairs of disulfide-bridged chains corresponding in most respects to mammalian fibrinogen chains.

Potential of High-Resolution Mass Spectrometry for the Detection of Drugs and Metabolites in Hair: Methoxetamine in a Real Forensic Case

2020 ◽  
Author(s):  
J M Matey ◽  
Adrián López-Fernández ◽  
Carmen García-Ruiz ◽  
Gemma Montalvo ◽  
M D Moreno ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Drugs Of Abuse ◽  
High Resolution Mass Spectrometry ◽  
High Resolution Mass ◽  
Low Concentrations ◽  
Forensic Case ◽  
High Resolution Technique ◽  
The One ◽  
Resolution Mass

Abstract The analysis of drugs of abuse in hair and other biological matrices of forensic interest requires great selectivity and sensitivity. This is done traditionally through target analysis, with one or more analytical methods, or with different and specific preanalytical phases, and complex procedures performed by the toxicological laboratories, and there is no exception with ketamine-like compounds, such as methoxetamine, a new psychoactive substance whose use has increased in the last decades, and continues to grow quickly year by year. More validated methods of analysis are needed to detect these substances in low concentrations selectively. Reanalyzing the samples of a former case of a polydrug consumer accused of a crime against public health in Spain, five metabolites of methoxetamine (normethoxetamine, O-desmethylmethoxetamine, dehydromethoxetamine, dihydronormethoxetamine and hydroxynormethoxetamine) were tentatively detected using a high-resolution technique, i.e., liquid chromatography coupled to high-resolution mass spectrometry (LC–HR-MS-MS). The highest analytical selectivity of LC–HR-MS-MS method together a universal and simpler pretreatment stages has demonstrated to allow faster analysis and more sensitivity than the one performed traditionally at the INTCF laboratories, which was gas chromatography coupled to mass spectrometry.

Detection of functional receptors for the proteinase-activated-receptor-2-activating polypeptide, SLIGRL-NH2, in rat vascular and gastric smooth muscle

1995 ◽  
Vol 73 (8) ◽  
pp. 1203-1207 ◽  
Author(s):  
Bahjaf Al-Ani ◽  
Mahmoud Saifeddine ◽  
Morley D. Hollenberg
Keyword(s):  
Smooth Muscle ◽  
Longitudinal Muscle ◽  
Rat Aorta ◽  
Peptide Sequence ◽  
Nitric Oxide Synthase Inhibitor ◽  
Aorta Ring ◽  
Gastric Smooth Muscle ◽  
Low Concentrations ◽  
The One ◽  
Synthase Inhibitor

We have studied the actions of the proteinase-activated-receptor-2 (PAR2)-activating polypeptide, SLIGRL-NH2 (SLI-NH2), in rat aorta and in gastric longitudinal muscle preparations. In the phenylephrine-precontracted aorta preparation, SLI-NH2 caused an endothelium-dependent relaxation that mimicked the action of low concentrations (0.5 U/mL) of trypsin and that was blocked by the nitric oxide synthase inhibitor Nω-nitro-L-arginine methyl ester. In endothelium-free aorta ring preparations, SLI-NH2 caused neither a relaxation nor a contraction. In the gastric longitudinal muscle preparation, SLI-NH2 caused a transient contraction that mimicked the action of trypsin (0.5 U/mL) and that was sensitive to inhibitors of cyclooxygenase (indomethacin) and tyrosine kinase (genistein). Further, using a reverse-transcriptase – polymerase chain reaction (RT–PCR) approach we detected, in both assay tissues, mRNA for the rat PAR2 receptor, and we ascertained, using a cloned receptor cDNA obtained from a rat intestinal cDNA library, that the putative N-terminal activating peptide sequence of the rat PAR2 receptor (SLIGRL) is identical with the one previously cloned from murine tissue. We concluded that, like the thrombin receptor, the PAR2 receptor may play a pathophysiologic role in the regulation of vascular and gastric smooth muscle contractility.Key words: thrombin, proteinase-activated receptor 2, protease, smooth muscle.

scholarly journals Structural and functional studies on the human hepatic interleukin-6 receptor. Molecular cloning and overexpression in HepG2 cells

1991 ◽  
Vol 277 (3) ◽  
pp. 659-664 ◽  
Author(s):  
H Schooltink ◽  
T Stoyan ◽  
D Lenz ◽  
H Schmitz ◽  
T Hirano ◽  
...  
Keyword(s):  
Interleukin 6 ◽  
Hepg2 Cells ◽  
Polyclonal Antiserum ◽  
Cross Linking ◽  
Human Hepatoma Cells ◽  
Functional Studies ◽  
Low Concentrations ◽  
Interleukin 6 Receptor ◽  
Cloned Cdna ◽  
The One

cDNAs coding for the human hepatic interleukin-6 receptor (IL-6-R) have been isolated from a library made from poly(A) RNA of dexamethasone-treated human hepatoma cells (HepG2). We found the hepatic IL-6-R to be identical to the one expressed by leucocytes. A polyclonal antiserum was raised in rabbits against the IL-6-R protein expressed in Escherichia coli. Although the entire IL-6-R protein was used for immunization, only antibodies to the cytoplasmic domain of the IL-6-R were obtained. It is demonstrated by affinity cross-linking and subsequent immunoprecipitation with antibodies against the ligand as well as against the receptor that the cloned cDNA codes for the functional IL-6-R on HepG2 cells. When the hepatic IL-6-R cDNA was overexpressed in HepG2 cells, these cells became more sensitive to low concentrations of IL-6 with respect to the induction of gamma-fibrinogen mRNA.

The Microchemical Analysis of Rubber

1954 ◽  
Vol 27 (2) ◽  
pp. 521-527 ◽  
Author(s):  
G. H. Wyatt
Keyword(s):  
Natural Rubber ◽  
Ph Value ◽  
Copper Wire ◽  
Potassium Chromate ◽  
Small Samples ◽  
Bunsen Flame ◽  
Microchemical Analysis ◽  
Red Color ◽  
Violet Color ◽  
Spot Tests

Abstract While those who profess to be microchemists have a number of specialized techniques, it is surprising how often microchemistry is used without appreciation that this is being done. As examples in the analysis of rubber, two qualitative color tests may be mentioned that are both applicable to small samples. The first was described by Weber in 1900, but interest in it has been revised recently by Stern and by Parker and Wake. In this test the rubber is treated with bromine and then with phenol; natural rubber gives a violet color and so may be distinguished from synthetic elastomers. In the second test, due to Kirchhof, natural rubber is detected by the yellow-to-red color which it gives with trichloroacetic acid. Other reactions carried out with small quantities of rubber for identification purposes include the well known Beilstein test for halogens, in which the organic substance when heated on a copper wire imparts a green color to a Bunsen flame. This method was suggested by Newton for the detection of chloroprenes, and has been applied by Shaw in a systematic procedure for the identification of plastics in general. Spot tests have also been devised that depend on the reactions of the vapors produced by destructive distillation of the rubber being examined; for example, Neoprene gives vapors which bleach paper impregnated with potassium chromate, or the density and pH value of the distillate may be determined. The rates of reaction of natural rubber and various synthetic elastomers with mixed nitric and sulfuric acids has been shown to be characteristic and may be determined with small samples. In contrast with the above, some procedures have been called micromethods by their advocates merely because the samples used are smaller than usual. Microchemistry was clearly defined by Emich as covering the range 2 to 10 mg. of substance, and the present author's work described below should properly be termed semimicroanalysis.

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