scholarly journals Synthesis of Biologically Active 4-Arylideneamino-2,4-dihydro-3H-1,2,4-triazol-3-one Compound by Ultrasonic Radiation and Conventional Method, Comparison of Methods and Elucidation of Structure

2021 ◽  
Author(s):  
İnci Selin DOĞAN ◽  
Bahittin KAHVECİ
Keyword(s):  
Conventional Method ◽  
Method Comparison ◽  
Biologically Active ◽  
Comparison Of Methods ◽  
Ultrasonic Radiation

Evaluation of determination of glucose in urine with some commercially available dipsticks and tablets.

1982 ◽  
Vol 28 (10) ◽  
pp. 2110-2115 ◽  
Author(s):  
Z L Bandi ◽  
J L Myers ◽  
D E Bee ◽  
G P James
Keyword(s):  
Method Comparison ◽  
Urine Samples ◽  
Comparison Of Methods ◽  
Urine Glucose ◽  
Glucose Determination ◽  
Upper Limit ◽  
Analytical Recovery ◽  
Precision And Accuracy ◽  
Analytical Errors

Abstract Four commercial products for urine glucose determination were evaluated and compared with a quantitative hexokinase procedure. We examined precision, sensitivity, and analytical recovery of glucose from glucose-supplemented urine samples and comparison of methods, using patients' samples. Only "Chemstrip uG" (Bio-Dynamics Inc.) could differentiate between 0.3 g/L (upper limit of normal) and 0.6 g/L urine glucose concentrations. "Tes-Tape" (Lilly) and "Diastix" (Ames) gave positive readings at 0.3 g/L; "Clinitest" (Ames) detected glucose only over 1 g/L. Analytical recovery of glucose was best, for all four products, between 1 and 2.5 g/L; Chemstrip uG was the most nearly accurate among the four. Between 5 and 20 g/L glucose concentrations, Tes-Tape, Diastix, and Clinitest tended to give falsely low results; the use of Chemstrip uG resulted in overestimates of concentration at 20 g of glucose per liter. Only Chemistrip uG and Clinitest (two-drop method) had linear ranges extending to 50 g/L; Chemstrip uG had better precision and accuracy at this concentration. Of the four products, Chemstrip uG had the lowest within-technologist and technologist-to-technologist random analytical errors. In method comparison on patients' samples, Chemstrip uG was significantly stronger in its association with the quantitative hexokinase method than was Diastix, Clinitest, or Tes-Tape.

scholarly journals An Intact ACTH LC-MS/MS Assay as an Arbiter of Clinically Discordant Immunoassay Results

2019 ◽  
Vol 65 (11) ◽  
pp. 1397-1404 ◽  
Author(s):  
Junyan Shi ◽  
Pawan Dhaliwal ◽  
Yu Zi Zheng ◽  
Terry Wong ◽  
Joely A Straseski ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Adrenocorticotropic Hormone ◽  
Epitope Mapping ◽  
Multiple Reaction Monitoring ◽  
Method Comparison ◽  
Biologically Active ◽  
Chromatography Tandem Mass Spectrometry ◽  
Ms Analysis ◽  
Liquid Chromatography Tandem Mass ◽  
Active Fragments

Abstract BACKGROUND Measurement of plasma adrenocorticotropic hormone (ACTH) is key in the differential diagnosis of hypothalamic-pituitary-adrenal disorders. Two-site sandwich immunoassays dominate clinical testing of ACTH in North America; however, discordant results between manufacturers have been repeatedly reported. To resolve the discrepancy, we developed a liquid chromatography–tandem mass spectrometry (LC-MS/MS) assay for the intended measurand, biologically active intact ACTH (iACTH). METHODS The multiple reaction monitoring LC-MS/MS assay was designed to selectively measure full-length iACTH, as well as ACTH analogs and fragments (i.e., ACTH1–24 and ACTH18–39). Epitope assignment of the Roche Elecsys antibodies was performed by MALDI-TOF mass spectrometry. A method comparison between Roche Elecsys and Siemens Immulite ACTH immunoassays was performed and clinically concordant/discordant results identified. In a subset of these samples, the iACTH concentration was determined using the LC-MS/MS method. RESULTS The lower limit of the measuring interval of the iACTH LC-MS/MS assay was 9 pg/mL (2 pmol/L). The assay was linear from 9 to 1938 pg/mL (2 to 427 pmol/L). Epitope mapping revealed that the Roche capture and detection antibodies bound residues 9–12 and 36–39 of ACTH, respectively. The iACTH LC-MS/MS analysis demonstrated that for discordant results between 2 immunoassays studied, only the Roche results were highly positively correlated with the iACTH concentration. CONCLUSIONS Immunoprecipitation of biologically active ACTH molecules followed by LC-MS/MS analysis enabled selective detection of iACTH and relevant biologically active fragments in plasma. Applied to the investigation of clinically discrepant results, this method can act as an arbiter of the concentration of iACTH present.

scholarly journals Tannins Extraction of Tea Leaves by Ultrasonic Method: Comparison with The Conventional Method

2020 ◽  
Vol 8 (1) ◽  
pp. 84-95
Author(s):  
Herliati Rahman ◽  
Shafira Fildza Arini ◽  
Vredyta Utomo
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Conventional Method ◽  
Camellia Sinensis ◽  
Ultrasonic Method ◽  
Method Comparison ◽  
Tea Leaves ◽  
Scanning Electron

Tanin merupakan senyawa polifenol yang berasal dari tumbuhan yang terdapat pada daun teh (Camellia sinensis). Umumnya tanin dipisahkan dari daun teh menggunakan ekstraksi pelarut. Sayangnya metode tersebut memberikan hasil yang kurang memuaskan, sehingga perlu dilakukan cara lain untuk mengatasi hal tersebut yaitu dengan metode ekstraksi ultrasonik. Penelitian ini bertujuan untuk mempelajari pengaruh ultrasonik terhadap peningkatan yield tanin hasil ekstraksi. Parameter yang diamati pada penelitian ini diantaranya waktu ekstraksi dan jenis daun teh yang digunakan dari tiga daerah dengan ketinggian dari permukaan laut yang berbeda, yaitu Ciwidey Bandung, Pagar Alam, dan Puncak Bogor. Variasi waktu ekstraksi yang digunakan adalah 4, 6, dan 8 jam dimana frekuensi ultrasonik pada 75 kHz dengan pelarut ethanol 70%. Produk yang mengandung tanin dianalisis secara kualitatif dan kuantitatif. Kadar tanin secara kualitatif diuji menggunakan FeCl3 dan Gelatin sedangkan analisis kuantitatif menggunakan spektrofotometer UV-vis Shimadzu UV 1800. Selain itu, karakterisasi Scanning Electron Microscopy (SEM) memberikan validasi bahwa metode ultrasonik berpengaruh terhadap peningkatan rendemen tanin. Hasil tertinggi diperoleh pada teh jenis Pagar Alam dengan waktu ekstraksi 8 jam, yaitu 23,1% yield dimana lebih tinggi 3% dibandingkan dengan metode konvensional.

scholarly journals A review on synthesis methods of tricyclic 1,2,3,4-tetrahydrocarbazoles

2022 ◽  
Vol 13 (1) ◽  
pp. 160-171
Author(s):  
Nitin Kumar ◽  
Vinod Kumar ◽  
Yogita Chowdhary
Keyword(s):  
Conventional Method ◽  
Review Article ◽  
Biologically Active ◽  
Synthetic Methods ◽  
Synthesis Methods ◽  
Microwave Method ◽  
Selective Method ◽  
Percentage Yield ◽  
Good Percentage

In this review article, we discussed old to new synthetic methods used for the preparation of 1,2,3,4-Tetrahydrocarbazole (THCz) based on reported literature. Around the worldwide, various researchers energetically reported new synthetic methods for tetrahydrocarbazoles preparation using conventional method or microwave method or use of catalyst. This review will be helpful to synthetic and medicinal chemist to find selective method for the preparation of 1,2,3,4-Tetrahydrocarbazoles with good percentage yield and less time. This review will also useful to medicinal chemist to design new biologically active tetrahydrocarbazoles based on reported synthetic methods.

Characterization of photosystem II with the atomic-force microscope

1992 ◽  
Vol 50 (2) ◽  
pp. 1146-1147
Author(s):  
Kathleen M. Marr ◽  
Mary K. Lyon
Keyword(s):  
Photosystem Ii ◽  
Atomic Force Microscope ◽  
Three Dimensional ◽  
Biologically Active ◽  
Atomic Force ◽  
Freeze Etching ◽  
Image Averaging ◽  
Oxygen Evolving ◽  
Averaging Techniques

Photosystem II (PSII) is different from all other reaction centers in that it splits water to evolve oxygen and hydrogen ions. This unique ability to evolve oxygen is partly due to three oxygen evolving polypeptides (OEPs) associated with the PSII complex. Freeze etching on grana derived insideout membranes revealed that the OEPs contribute to the observed tetrameric nature of the PSIl particle; when the OEPs are removed, a distinct dimer emerges. Thus, the surface of the PSII complex changes dramatically upon removal of these polypeptides. The atomic force microscope (AFM) is ideal for examining surface topography. The instrument provides a topographical view of individual PSII complexes, giving relatively high resolution three-dimensional information without image averaging techniques. In addition, the use of a fluid cell allows a biologically active sample to be maintained under fully hydrated and physiologically buffered conditions. The OEPs associated with PSII may be sequentially removed, thereby changing the surface of the complex by one polypeptide at a time.

Depletion and Reconstitution of Active E. Coli Ribosomes

1975 ◽  
Vol 33 ◽  
pp. 640-641
Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins
Keyword(s):  
Protein Biosynthesis ◽  
Large Subunit ◽  
High Resolution Electron Microscopy ◽  
Small Subunit ◽  
Structure And Function ◽  
Biologically Active ◽  
Biological Macromolecules ◽  
E Coli ◽  
Resolution Electron ◽  
And Function

Correlations between structure and function of biological macromolecules have been studied intensively for many years, mostly by indirect methods. High resolution electron microscopy is a unique tool which can provide such information directly by comparing the conformation of biopolymers in their biologically active and inactive state. We have correlated the structure and function of ribosomes, ribonucleoprotein particles which are the site of protein biosynthesis. 70S E. coli ribosomes, used in this experiment, are composed of two subunits - large (50S) and small (30S). The large subunit consists of 34 proteins and two different ribonucleic acid molecules. The small subunit contains 21 proteins and one RNA molecule. All proteins (with the exception of L7 and L12) are present in one copy per ribosome.This study deals with the changes in the fine structure of E. coli ribosomes depleted of proteins L7 and L12. These proteins are unique in many aspects.

Fractionation of the Biologically Active Large Molecular Components of Human Gastric Content

1959 ◽  
Vol 37 (4) ◽  
pp. 439-444 ◽  
Author(s):  
Ranwel Caputto ◽  
William O. Smith ◽  
Jordan Tang ◽  
Raul E. Trucco ◽  
Walter Joel ◽  
...  
Keyword(s):  
Gastric Content ◽  
Biologically Active ◽  
Molecular Components
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