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Spectrophotometric estimation

Hamid Reza Rajabi, Fatemeh Karimi, Hossein Kazemdehdashti, Leila Kavoshi
In this research, a sono-assisted chemical precipitation method was developed for a quick and efficient water-based synthesis of zinc sulfide (ZnS) quantum dots (QDs), in room temperature. ZnS QDs as pure and doped with some transition metal ions (such as Cu2+ , Mn2+ , Ag+ ) were prepared in the presence of l-cysteine, as capping agent. In comparison with the previous conventional methods, applying the ultrasonic irradiation provides a significant decrease in the reaction time. In comparison with previous reported conventional chemical QD synthesis methods, the required time for a complete synthesis in the presence of ultrasonic irradiations was significantly reduced to a period as short as 15 min, in a temperature of 40 °C...
February 22, 2018: Journal of Photochemistry and Photobiology. B, Biology
Łukasz Murlikiewicz, Krzysztof Grzegorczyk, Małgorzata Lewicka, Andrzej Buczyński, Maciej Rutkowski
BACKGROUND: Thus far, the pathogenesis of these intestinal tumors has not been fully explained. However, the analysis of risk factors and research regarding their formation that have continued for 3 decades have allowed us to demonstrate a significant role of oxidative stress in the processes leading to the development of cancer in the large intestine as well as in some other organs. OBJECTIVES: The aim of the study was to examine the level of anti-oxidative status and the degree of oxidative protein damage in patients with varying severity of colonic adenocarcinoma (CAC) in relation to healthy individuals...
January 2018: Advances in Clinical and Experimental Medicine: Official Organ Wroclaw Medical University
Vineet K Singh, Sirisha Sirobhushanam, Robert P Ring, Saumya Singh, Craig Gatto, Brian J Wilkinson
PURPOSE: Membrane fluidity to a large extent is governed by the presence of branched-chain fatty acids (BCFAs). Branched-chain α-keto acid dehydrogenase (BKD) is the key enzyme in BCFA synthesis. A Staphylococcus aureus BKD-deficient strain still produced substantial levels of BCFAs. Pyruvate dehydrogenase (PDH) with structural similarity to BKD has been speculated to contribute to BCFAs in S. aureus. METHODOLOGY: This study was carried out using BKD-, PDH- and BKD : PDH-deficient derivatives of methicillin-resistant S...
March 2, 2018: Journal of Medical Microbiology
Kazuhide Miyamoto, Ayumi Yamashita, Kazuki Saito
Cross-brace structural motifs are required as a scaffold to design artificial RING fingers (ARFs) that function as ubiquitin ligase (E3) in ubiquitination and have specific ubiquitin-conjugating enzyme (E2)-binding capabilities. The Simple Modular Architecture Research Tool database predicted the amino acid sequence 131-190 (KIAA1045ZF) of the human KIAA1045 protein as an unidentified structural region. Herein, the stoichiometry of zinc ions estimated spectrophotometrically by the metallochromic indicator revealed that the KIAA1045ZF motif binds to two zinc atoms...
February 12, 2018: Protein Science: a Publication of the Protein Society
Maria Ashfaq, Ali Akber Sial, Rabia Bushra, Atta-Ur Rehman, Mirza Tasawur Baig, Ambreen Huma, Maryam Ahmed
Spectrophotometric technique is considered to be the simplest and operator friendly among other available analytical methods for pharmaceutical analysis. The objective of the study was to develop a precise, accurate and rapid UV-spectrophotometric method for the estimation of chlorpheniramine maleate (CPM) in pure and solid pharmaceutical formulation. Drug absorption was measured in various solvent systems including 0.1N HCl (pH 1.2), acetate buffer (pH 4.5), phosphate buffer (pH 6.8) and distil water (pH 7...
January 2018: Pakistan Journal of Pharmaceutical Sciences
Anita S Iyer, Andrew S Azman, Malika Bouhenia, Lul O Deng, Cole P Anderson, Michael Graves, Pavol Kováč, Peng Xu, Edward T Ryan, Jason B Harris, David A Sack, Francisco J Luquero, Daniel T Leung
BACKGROUND: Vibrio cholerae causes over 2 million cases of cholera and 90,000 deaths each year. Serosurveillance can be a useful tool for estimating the intensity of cholera transmission and prioritizing populations for cholera control interventions. Current methods involving venous blood draws and downstream specimen storage and transport methods pose logistical challenges in most settings where cholera strikes. To overcome these challenges, we developed methods for determining cholera-specific immune responses from dried blood spots (DBS)...
January 29, 2018: PLoS Neglected Tropical Diseases
Alma Betsaida Benitez-Trinidad, Irma Martha Medina-Díaz, Yael Yvette Bernal-Hernández, Briscia Socorro Barrón-Vivanco, Cyndia Azucena González-Arias, José Francisco Herrera-Moreno, Isabel Alvarado-Cruz, Betzabet Quintanilla-Vega, Aurora Elizabeth Rojas-García
Recently a relationship has been reported between pesticide exposure and changes in global DNA methylation patterns. Urban sprayers are a particularly vulnerable population because of the high risk of pesticide exposure that their work implies. Therefore, the aim of this study was to estimate the changes in the Long Interspersed Nucleotide Element (LINE-1) in urban sprayers and its relationship with pesticide exposure. The study population consisted of 190 individuals stratified into three study groups: no occupational pesticide exposure; moderate exposure, and high exposure...
January 25, 2018: Food and Chemical Toxicology
Eliezer Oliveira, Camelia Henriquez, Lidiane C Nunes, Elias A G Zagatto
Multivariate calibration involving partial least squares was exploited in the flow-based spectrophotometric determination of molybdenum in river waters relying on the Mo(VI)-catalyzed iodide oxidation by H2O2 under acidic conditions. Two sample aliquots were simultaneously inserted into the carrier stream, and differential pumping was accountable for in-line addition of sulfuric acid to one of them. Pronounced gradients (acidity and reagent concentrations) were established along the complex sample zone formed, and the absorbance-time function was characterized by local maximum and minimum values...
March 1, 2018: Talanta
Karel Van Keer, Jan Van Keer, João Barbosa Breda, Vahid Nassiri, Cathy De Deyne, Cornelia Genbrugge, Luís Abegão Pinto, Ingeborg Stalmans, Evelien Vandewalle
BACKGROUND: To investigate the correlation between cerebral (SO2-transcranial), retinal arterial (SaO2-retinal) and venous (SvO2-retinal) oxygen saturation as measured by near-infrared spectroscopy (NIRS) and retinal oximetry respectively. METHODS: Paired retinal and cerebral oxygen saturation measurements were performed in healthy volunteers. Arterial and venous retinal oxygen saturation and diameter were measured using a non-invasive spectrophotometric retinal oximeter...
2018: PloS One
Kumar Parida Soumendra, T Guruprasad, V B Krishnakumar Raja, Poornima Ravi
PURPOSE: This study aimed at assessing the change in salivary opiorphin levels before and after administration of local anesthesia, with the use of three different local anesthetic agents, and different anaesthetic techniques. METHODS: The investigators implemented a randomized controlled clinical study in 144 patients who required tooth extraction after administration of local anaesthesia. A total of 288 samples were collected in sterile containers before and after administration of local anesthetics...
December 13, 2017: Journal of Stomatology, Oral and Maxillofacial Surgery
Sana Ghayas, Muhammad Harris Shoaib, Fahad Siddiqui, Rabia Ismail Yousuf, M Ali Masood, Fakhsheena Anjum, Rabia Bushra, Lubna Bashir, Shazia Naz, Iyad Naeem Muhammad
A swift, precise and simple HPLC bioanalytical technique with UV detection was established and validated for quantitative estimation of valsartan in human plasma. The analyte was separated from plasma by protein precipitation with acetonitrile and chromatographically separated on Zorbax SB-C18 (5μm, 4.6mm × 15cm) column. The solvent mixture system consisting of acetonitrile, water and glacial acetic acid (40:59:1 v/v), was pumped using isocratic mode at 1mL/min flow rate. Samples' detection of drug was made spectrophotometrically at a wavelength of 264nm...
November 2017: Pakistan Journal of Pharmaceutical Sciences
Attaur Rehman, Anwar Ejaz Beg, Rabia Bushra, Maria Ashfaq, Farya Zafar, Huma Ali, Mehwish Rizvi
A simple stability indicating UV-spectrophotometric method has been developed and validated for the determination of cinitapride hydrogen tartrate (CHT) in bulk and solid pharmaceutical dosage form. Drug absorption was measured in different analytical mediums however; maximum absorption was seen in 0.1 N HCl at wavelength (λmax) of 266 nm. The calibration curve was found to be linear over the concentration range from 6 to14μg/mL with the correlation coefficient value (r) of 0.999. The LOD and LOQ were estimated to be 0...
November 2017: Pakistan Journal of Pharmaceutical Sciences
Nikolina Maček Hrvat, Tamara Zorbaz, Goran Šinko, Zrinka Kovarik
Reactivation of acetylcholinesterase (AChE), an essential enzyme in neurotransmission, is a key point in the treatment of acute poisoning by nerve agents and pesticides, which structurally belong to organophosphorus compounds (OP). Due to the high diversity of substituents on the phosphorous atom, there is a variety of OP-AChE conjugates deriving from AChE inhibition, and therefore not only is there no universal reactivator efficient enough for the most toxic OPs, but for some nerve agents there is still a lack of any reactivator at all...
November 24, 2017: Toxicology Letters
Magda M Ayad, Fathalla Belal, Mervet M Hosney, Samah Abo El Abass, Nora Elsayed
Two simple and sensitive analytical assay methods using spectrophotometry and spectrofluorimetry techniques were developed for the estimation of succinylcholine chloride (SUC) in pharmaceutical preparations. The suggested methods are based on the formation of an ion pair complex formed between the drug and eosin Y spectrophotometrically (Method I), or the suppressive effect of succinylcholine on the native fluorescence property of eosin Y (Method II). The spectrophotometric method (Method I) involves measuring the absorbance of the complex between succinylcholine and eosin Y at 550 nm in Britton Robinson buffer of pH 3...
November 8, 2017: Luminescence: the Journal of Biological and Chemical Luminescence
M Thomas Morgan, Lily Anh H Nguyen, Haylie L Hancock, Christoph J Fahrni
The tripeptide glutathione (GSH) is a crucial intracellular reductant and radical scavenger, but may also coordinate the soft Cu(I) cation and thereby yield pro-oxidant species. The GSH-Cu(I) interaction is thus a key consideration for both redox and copper homeostasis in cells. However, even after nearly four decades of investigation, the nature and stability of the GSH-Cu complexes formed under biologically relevant conditions remain controversial. Here, we revealed the unexpected predominance of a tetranuclear [Cu4(GS)6] cluster that is sufficiently stable to limit the effective free aquocopper(I) concentration to the subfemtomolar regime...
November 3, 2017: Journal of Biological Chemistry
Aleksandra Rył, Iwona Rotter, Anna Grzywacz, Iwona Małecka, Karolina Skonieczna-Żydecka, Katarzyna Grzesiak, Marcin Słojewski, Aleksandra Szylińska, Olimpia Sipak-Szmigiel, Małgorzata Piasecka, Kinga Walczakiewicz, Maria Laszczyńska
Introduction : The etiology of benign prostatic hyperplasia (BPH) has not so far been fully explicated. However, it is assumed that changes in the levels of hormones associated with aging can contribute to the development of prostatic hyperplasia. Dihydrotestosterone combines with the androgen receptor (AR) proteins of the prostate gland. Enzyme activity is based on two isoenzymes: type 1 and type 2. 5α-reductase type 1 is encoded by the SRD5A1 gene, and type 2 is encoded by the SRD5A2 gene. The aim of our study was to determine the frequency of the SRD5A1 (rs6884552, rs3797177) and SRD5A2 (rs523349, rs12470143) genes' polymorphisms, and to assess the relationships between the genotypes of the tested mutations, and the levels of biochemical and hormonal parameters in patients with BPH...
October 30, 2017: International Journal of Environmental Research and Public Health
Baishnisha Amanulla, Selvakumar Palanisamy, Shen-Ming Chen, Te-Wei Chiu, Vijayalakshmi Velusamy, James M Hall, Tse-Wei Chen, Sayee Kannan Ramaraj
Excess nitrite (NO2(-)) concentrations in water supplies is considered detrimental to the environment and human health, and is associated with incidence of stomach cancer. In this work, the authors describe a nitrite detection system based on the synthesis of gold nanoparticles (AuNPs) on reduced graphene oxide (rGO) using an aqueous solution of chitosan and succinic acid. The AuNPs-rGO nanocomposite was confirmed by different physicochemical characterization methods including transmission electron microscopy, elemental analysis, X-ray diffraction, UV-visible (UV-vis) and Fourier transform infrared spectroscopy...
October 27, 2017: Scientific Reports
Alexander M Liudchik, Pavel N Paulenka
A rigorous theoretical description of the standard spectrophotometric method for determining medium composition is given using a vector representation of measured signals. Further modifications, methods of orthogonal optical absorption spectroscopy (OOAS) and differential optical absorption spectroscopy (DOAS), are also substantiated. It is shown that the conventional criterion, the difference between the measured spectrum and the spectrum simulated on the basis of calculations, does not serve as an indicator of quality of the latter...
September 20, 2017: Applied Optics
Farya Zafar, Muhammad Harris Shoaib, Rabia Ismail Yousuf, Huma Ali, Rabia Bushra
In the present study the pharmacokinetic and bioequivalence parameter of Ketoprofen 100 mg fast dispersible tablets (test) were measured with marketed (reference) product. This study was accomplished following FDA guidance. A single dose, open labeled, cross over (two way), randomized study design was used to conduct investigation on 12 Pakistani healthy volunteers. At various time points blood samples (10mL) were drawn i.e. at 0.25, 0.5, 1, 1.5, 2, 3, 4, 8, 12 and 13hr. Plasma was then separated and ketoprofen concentrations were estimated by validated HPLC technique using LC 20A pump (Shimadzu Corp, Japan) and Spectrophotometric SPD-20Adetector (Shimadzu Corp, Japan)...
July 2017: Pakistan Journal of Pharmaceutical Sciences
Hamid Reza Akbari Hasanjani, Mahmoud Reza Sohrabi
Simultaneous spectrophotometric estimation of Fluoxetine and Sertraline in tablets were performed using UV-Vis spectroscopic and Artificial Neural Networks (ANN). Absorption spectra of two components were recorded in 200-300 nm wavelengths region with an interval of 1 nm. The calibration models were thoroughly evaluated at several concentration levels using the spectra of synthetic binary mixture (prepared using orthogonal design). Three layers feed-forward neural networks using the back-propagation algorithm (B...
2017: Iranian Journal of Pharmaceutical Research: IJPR
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